Journal Description
C — Journal of Carbon Research
C
— Journal of Carbon Research is an international, scientific, peer-reviewed, open access journal on carbon research, published quarterly online by MDPI. The Spanish Carbon Group (GEC) is affiliated with C — Journal of Carbon Research and its members receive discounts on article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within ESCI (Web of Science), Scopus, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q2 (Materials Science, Multidisciplinary)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 19.8 days after submission; acceptance to publication is undertaken in 3.6 days (median values for papers published in this journal in the first half of 2024).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
3.9 (2023);
5-Year Impact Factor:
4.0 (2023)
Latest Articles
Adsorption on Carbon-Based Materials
C 2024, 10(4), 102; https://doi.org/10.3390/c10040102 - 4 Dec 2024
Abstract
Polluted streams, both in their gas and liquid phases, constitute a potential menace to the environment and to living organisms [...]
Full article
(This article belongs to the Special Issue Adsorption on Carbon-Based Materials)
Open AccessEditorial
Carbon and Related Composites for Sensors and Energy Storage: Synthesis, Properties, and Application
by
Olena Okhay and Gil Goncalves
C 2024, 10(4), 101; https://doi.org/10.3390/c10040101 - 3 Dec 2024
Abstract
In recent years, mankind’s energy needs have been increasing; therefore, current research is focused on the collection and storage of energy [...]
Full article
(This article belongs to the Special Issue Carbon and Related Composites for Sensors and Energy Storage: Synthesis, Properties, and Application)
Open AccessArticle
Cocoa Pod Husk Carbon Family for Biogas Upgrading: Preliminary Assessment Using the Approximate Adsorption Performance Indicator
by
Khaled Abou Alfa, Diana C. Meza-Sepulveda, Cyril Vaulot, Jean-Marc Le Meins, Camelia Matei Ghimbeu, Louise Tonini, Janneth A. Cubillos, Laurent Moynault, Vincent Platel, Diego Paredes and Cecile Hort
C 2024, 10(4), 100; https://doi.org/10.3390/c10040100 - 29 Nov 2024
Abstract
The preliminary selection of adsorbents for the separation of a gas mixture based on pure gas adsorption remains a critical challenge; thus, an approximate adsorption performance indicator (AAPI) was proposed for the initial evaluation of the adsorbents to separate the biogas main constituents
[...] Read more.
The preliminary selection of adsorbents for the separation of a gas mixture based on pure gas adsorption remains a critical challenge; thus, an approximate adsorption performance indicator (AAPI) was proposed for the initial evaluation of the adsorbents to separate the biogas main constituents (carbon dioxide/methane (CO2/CH4)) by studying their pure gas adsorption. Three samples derived from cocoa pod husk (CPH), namely Cabosse-500 (pyrolyzed at 500 °C), Cabosse-700 (pyrolyzed at 700 °C), and Cabosse-A-700 (activated with CO2 at 700 °C), were synthesized, characterized, and evaluated for the pure gases adsorption. This study presents an AAPI evaluation, which takes into account adsorption capacity, approximate selectivity, and heat of adsorption. Adsorption isotherms indicate the ability of the CPH family to selectively capture CO2 over CH4, as they have a high approximate selectivity (>1) thanks to their physical properties. Changing the pyrolysis temperature, activation methods, and varying the pressure can significantly change the choice of the most effective adsorbent; Cabosse-A-700 showed better performance than the other two in the low and high pressure range owing to its presence of micropores and mesopores, which enhances the CO2 adsorption and therefore the AAPI.
Full article
(This article belongs to the Special Issue Carbon Functionalization: From Synthesis to Applications)
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>Biochars and activated biochar preparation.</p> Full article ">Figure 2
<p>Schematic of the calorimeter “micro DSC VII”.</p> Full article ">Figure 3
<p>Schematic representation of a high-pressure homemade manometric device.</p> Full article ">Figure 4
<p>Morphology of the CPH family obtained by SEM at different magnification scales (500 μm, 200 μm, and 100 μm) of (<b>a</b>) Cabosse-700 and (<b>b</b>) Cabosse-A-700.</p> Full article ">Figure 5
<p>XRD analysis of the CPH family. ∘ <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>CO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, □ <math display="inline"><semantics> <mrow> <msub> <mi>SiO</mi> <mn>2</mn> </msub> </mrow> </semantics></math>, Δ <math display="inline"><semantics> <mrow> <msub> <mi>CaCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, ✩ <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>SO</mi> <mn>4</mn> </msub> </mrow> </semantics></math>, ⋄ ClK, and × <math display="inline"><semantics> <mrow> <msub> <mi>MgCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>.</p> Full article ">Figure 6
<p>Thermogravimetric analysis curves for the CPH family (<b>a</b>) under <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">N</mi> <mn>2</mn> </msub> </mrow> </semantics></math> for Cabosse-500 and Cabosse-700 and <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">N</mi> <mn>2</mn> </msub> </mrow> </semantics></math> followed by air for raw CPH, (<b>b</b>) under air for Cabosse-500, Cabosse-700, and Cabosse-A-700.</p> Full article ">Figure 7
<p>(<b>a</b>) Adsorption–desorption isotherm of cabosse family (<math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">N</mi> <mn>2</mn> </msub> </mrow> </semantics></math>, 77 K). (<b>b</b>) Adsorption isotherm of Cabosse-700 and Cabosse-A-700 (<math display="inline"><semantics> <mrow> <msub> <mi>CO</mi> <mn>2</mn> </msub> </mrow> </semantics></math>, 273 K).</p> Full article ">Figure 8
<p>Heat of adsorption of the CPH family at 303 K as a function of pressure.</p> Full article ">Figure 9
<p><math display="inline"><semantics> <mrow> <msub> <mi>CO</mi> <mn>2</mn> </msub> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mi>CH</mi> <mn>4</mn> </msub> </mrow> </semantics></math> adsorption isotherms of the CPH family at 303 K as a function of pressure.</p> Full article ">Figure 10
<p>Scheme of <math display="inline"><semantics> <mrow> <msub> <mi>CO</mi> <mn>2</mn> </msub> </mrow> </semantics></math> adsorption on the CPH family in the presence of <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>CO</mi> <mn>3</mn> </msub> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>SO</mi> <mn>4</mn> </msub> </mrow> </semantics></math> under wet conditions.</p> Full article ">Figure 11
<p>XRD analysis of the activated biochar before and post <math display="inline"><semantics> <mrow> <msub> <mi>CO</mi> <mn>2</mn> </msub> </mrow> </semantics></math> adsorption (after three months) at low pressure and ambient conditions(air/humidity) storage. ⊗ <math display="inline"><semantics> <mrow> <msub> <mi>KHCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, ∘ <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>CO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, Δ <math display="inline"><semantics> <mrow> <msub> <mi>CaCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, □ <math display="inline"><semantics> <mrow> <msub> <mi>SiO</mi> <mn>2</mn> </msub> </mrow> </semantics></math>, and × <math display="inline"><semantics> <mrow> <msub> <mi>MgCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>.</p> Full article ">Figure 12
<p>AAPI values of the cabosse family at 303 K as a function of pressure. Uncertainty calculated using the propagation of errors formula.</p> Full article ">
Full article ">Figure 1
<p>Biochars and activated biochar preparation.</p> Full article ">Figure 2
<p>Schematic of the calorimeter “micro DSC VII”.</p> Full article ">Figure 3
<p>Schematic representation of a high-pressure homemade manometric device.</p> Full article ">Figure 4
<p>Morphology of the CPH family obtained by SEM at different magnification scales (500 μm, 200 μm, and 100 μm) of (<b>a</b>) Cabosse-700 and (<b>b</b>) Cabosse-A-700.</p> Full article ">Figure 5
<p>XRD analysis of the CPH family. ∘ <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>CO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, □ <math display="inline"><semantics> <mrow> <msub> <mi>SiO</mi> <mn>2</mn> </msub> </mrow> </semantics></math>, Δ <math display="inline"><semantics> <mrow> <msub> <mi>CaCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, ✩ <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>SO</mi> <mn>4</mn> </msub> </mrow> </semantics></math>, ⋄ ClK, and × <math display="inline"><semantics> <mrow> <msub> <mi>MgCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>.</p> Full article ">Figure 6
<p>Thermogravimetric analysis curves for the CPH family (<b>a</b>) under <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">N</mi> <mn>2</mn> </msub> </mrow> </semantics></math> for Cabosse-500 and Cabosse-700 and <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">N</mi> <mn>2</mn> </msub> </mrow> </semantics></math> followed by air for raw CPH, (<b>b</b>) under air for Cabosse-500, Cabosse-700, and Cabosse-A-700.</p> Full article ">Figure 7
<p>(<b>a</b>) Adsorption–desorption isotherm of cabosse family (<math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">N</mi> <mn>2</mn> </msub> </mrow> </semantics></math>, 77 K). (<b>b</b>) Adsorption isotherm of Cabosse-700 and Cabosse-A-700 (<math display="inline"><semantics> <mrow> <msub> <mi>CO</mi> <mn>2</mn> </msub> </mrow> </semantics></math>, 273 K).</p> Full article ">Figure 8
<p>Heat of adsorption of the CPH family at 303 K as a function of pressure.</p> Full article ">Figure 9
<p><math display="inline"><semantics> <mrow> <msub> <mi>CO</mi> <mn>2</mn> </msub> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mi>CH</mi> <mn>4</mn> </msub> </mrow> </semantics></math> adsorption isotherms of the CPH family at 303 K as a function of pressure.</p> Full article ">Figure 10
<p>Scheme of <math display="inline"><semantics> <mrow> <msub> <mi>CO</mi> <mn>2</mn> </msub> </mrow> </semantics></math> adsorption on the CPH family in the presence of <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>CO</mi> <mn>3</mn> </msub> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>SO</mi> <mn>4</mn> </msub> </mrow> </semantics></math> under wet conditions.</p> Full article ">Figure 11
<p>XRD analysis of the activated biochar before and post <math display="inline"><semantics> <mrow> <msub> <mi>CO</mi> <mn>2</mn> </msub> </mrow> </semantics></math> adsorption (after three months) at low pressure and ambient conditions(air/humidity) storage. ⊗ <math display="inline"><semantics> <mrow> <msub> <mi>KHCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, ∘ <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="normal">K</mi> <mn>2</mn> </msub> <msub> <mi>CO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, Δ <math display="inline"><semantics> <mrow> <msub> <mi>CaCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>, □ <math display="inline"><semantics> <mrow> <msub> <mi>SiO</mi> <mn>2</mn> </msub> </mrow> </semantics></math>, and × <math display="inline"><semantics> <mrow> <msub> <mi>MgCO</mi> <mn>3</mn> </msub> </mrow> </semantics></math>.</p> Full article ">Figure 12
<p>AAPI values of the cabosse family at 303 K as a function of pressure. Uncertainty calculated using the propagation of errors formula.</p> Full article ">
Open AccessArticle
Graphene Xerogel for Drug Release
by
Kyriaki Kalyva, Katerina Michalarou, Moch Izzul Haq Al Maruf and Vasilios I. Georgakilas
C 2024, 10(4), 99; https://doi.org/10.3390/c10040099 - 28 Nov 2024
Abstract
By functionalizing reduced graphene oxide with polydopamine, the production of a two-dimensional hydrophilicplatform with hydrophobic areas, suitable for the stabilization and slow and controlled release of hydrophilic and hydrophobic drugs, was realized. The functionalized graphene was first enriched with different organic drug molecules,
[...] Read more.
By functionalizing reduced graphene oxide with polydopamine, the production of a two-dimensional hydrophilicplatform with hydrophobic areas, suitable for the stabilization and slow and controlled release of hydrophilic and hydrophobic drugs, was realized. The functionalized graphene was first enriched with different organic drug molecules, either hydrophilic, such as doxorubicin, or hydrophobic, such as curcumin or quercetin, and then incorporated into a xerogel of chitosan and polyvinyl alcohol. The graphene substrate stabilizes the xerogel in water and effectively controls the release of doxorubicin for more than three weeks. The release of curcumin and quercetin in the aqueous environment was equally successful but at different rates. The drug-loaded xerogels also worked effectively after their incorporation into a hemostatic cotton gauze.
Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications (2nd Edition))
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>The formation of the rGO-PDA derivative and attachment of DOX (red colored) on rGO-PDA (rGO-PDA/DOX).</p> Full article ">Figure 2
<p>FTIR spectra of (<b>a</b>) GO, (<b>b</b>) rGO-PDA (<b>c</b>) Part of the spectrum (<b>a</b>) in magnification. and (<b>d</b>) UV-Vis spectra of GO and rGO-PDA dispersed in water.</p> Full article ">Figure 3
<p>(<b>a</b>) DLS analysis and (<b>b</b>) zeta potential of rGO-PDA (the red line represent Gauss fitting).</p> Full article ">Figure 4
<p>(<b>a</b>) The released amount of DOX per day from rGO-PDA/DOX hydrogel, (<b>b</b>) photo of the DOX-doped xerogel before and after the release process, (<b>c</b>) the release of DOX per day from the gauze modified with rGO-PDA/DOX hydrogel, (<b>d</b>) the UV-Vis spectra of DOX and rGO-PDA/Dox hybrid.</p> Full article ">Figure 5
<p>(<b>a</b>) The UV-Vis spectra of quercetin and rGO-PDA/Querc, (<b>b</b>) the release amount of quercetin per day from the gauze embedded with rGO-PDA/Querc hydrogel, (<b>c</b>) the suggested structure of rGO-PDA/Querc. (Querc is green colored).</p> Full article ">Figure 6
<p>(<b>a</b>) The release amount of curcumin per day from the gauze embedded with rGO-PDA/Curc hydrogel, (<b>b</b>) comparison of the drug release from the gauze embedded with the rGO-PDA hydrogels between the three drug substances, (<b>c</b>) the suggested structure of rGO-PDA/Curc, where Curc are blue colored, (<b>d</b>) the UV-Vis spectra of free curcumin and rGO-PDA/Curc.</p> Full article ">
Full article ">Figure 1
<p>The formation of the rGO-PDA derivative and attachment of DOX (red colored) on rGO-PDA (rGO-PDA/DOX).</p> Full article ">Figure 2
<p>FTIR spectra of (<b>a</b>) GO, (<b>b</b>) rGO-PDA (<b>c</b>) Part of the spectrum (<b>a</b>) in magnification. and (<b>d</b>) UV-Vis spectra of GO and rGO-PDA dispersed in water.</p> Full article ">Figure 3
<p>(<b>a</b>) DLS analysis and (<b>b</b>) zeta potential of rGO-PDA (the red line represent Gauss fitting).</p> Full article ">Figure 4
<p>(<b>a</b>) The released amount of DOX per day from rGO-PDA/DOX hydrogel, (<b>b</b>) photo of the DOX-doped xerogel before and after the release process, (<b>c</b>) the release of DOX per day from the gauze modified with rGO-PDA/DOX hydrogel, (<b>d</b>) the UV-Vis spectra of DOX and rGO-PDA/Dox hybrid.</p> Full article ">Figure 5
<p>(<b>a</b>) The UV-Vis spectra of quercetin and rGO-PDA/Querc, (<b>b</b>) the release amount of quercetin per day from the gauze embedded with rGO-PDA/Querc hydrogel, (<b>c</b>) the suggested structure of rGO-PDA/Querc. (Querc is green colored).</p> Full article ">Figure 6
<p>(<b>a</b>) The release amount of curcumin per day from the gauze embedded with rGO-PDA/Curc hydrogel, (<b>b</b>) comparison of the drug release from the gauze embedded with the rGO-PDA hydrogels between the three drug substances, (<b>c</b>) the suggested structure of rGO-PDA/Curc, where Curc are blue colored, (<b>d</b>) the UV-Vis spectra of free curcumin and rGO-PDA/Curc.</p> Full article ">
Open AccessReview
Graphitic Carbon Nitride: A Novel Two-Dimensional Metal-Free Carbon-Based Polymer Material for Electrochemical Detection of Biomarkers
by
Ganesan Kausalya Sasikumar, Pitchai Utchimahali Muthu Raja, Peter Jerome, Rathinasamy Radhamani Shenthilkumar and Putrakumar Balla
C 2024, 10(4), 98; https://doi.org/10.3390/c10040098 - 27 Nov 2024
Abstract
Graphitic carbon nitride (g-C3N4) has gained significant attention due to its unique physicochemical properties as a metal-free, two-dimensional, carbon-based polymeric fluorescent substance composed of tris-triazine-based patterns with a slight hydrogen content and a carbon-to-nitrogen ratio of 3:4. It forms
[...] Read more.
Graphitic carbon nitride (g-C3N4) has gained significant attention due to its unique physicochemical properties as a metal-free, two-dimensional, carbon-based polymeric fluorescent substance composed of tris-triazine-based patterns with a slight hydrogen content and a carbon-to-nitrogen ratio of 3:4. It forms layered structures like graphite and demonstrates exciting and unusual physicochemical properties, making g-C3N4 widely used in nanoelectronic devices, spin electronics, energy storage, thermal conductivity materials, and many others. The biomedical industry has greatly benefited from its excellent optical, electrical, and physicochemical characteristics, such as abundance on Earth, affordability, vast surface area, and fast synthesis. Notably, the heptazine phase of g-C3N4 displays stable electronic bands. Another significant quality of this semiconductor material is its excellent fluorescence property, which is also helpful in preparing biosensors. Based on g-C3N4, electrochemical biosensors have provided better biocompatibility, higher sensitivity, low detection limits, nontoxicity, excellent selectivity, and surface versatility of functionalization for the delicate identification of target analytes. This review covers the latest studies on using efflorescent graphitic carbon nitride to fabricate electrochemical biosensors for various biomarkers. Carbon nitrides have been reported to possess excellent electroactivity properties, a massive surface-to-volume ratio, and hydrogen-bonding functionality, thus allowing electrochemical-based, highly sensitive, and selective detection platforms for an entire array of analytes. Considering the preceding information, this review addresses the fundamentals and background of g-C3N4 and its numerous synthesis pathways. Furthermore, the importance of electrochemical sensing of diverse biomarkers is emphasized in this review article. It also discusses the current status of the challenges and future perspectives of graphitic carbon nitride-based electrochemical sensors, which open paths toward their practical application in aspects of clinical diagnostics.
Full article
(This article belongs to the Special Issue Carbon-Based Polymer Composites: Synthesis, Processing, Characterization and Applications)
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>Various phases of carbon nitride (CN).</p> Full article ">Figure 2
<p>g-C<sub>3</sub>N<sub>4</sub>: Electronic structure (<b>a</b>); Band gap (<b>b</b>); 2D representation with C and N (<b>c</b>).</p> Full article ">Figure 3
<p>Bulk g-C<sub>3</sub>N<sub>4</sub> from a different precursor material.</p> Full article ">Figure 4
<p>Morphology of g-C<sub>3</sub>N<sub>4</sub>.</p> Full article ">Figure 5
<p>Synthesis routes of g-C<sub>3</sub>N<sub>4</sub>.</p> Full article ">Figure 6
<p>Electrochemical sensing of various biomarkers.</p> Full article ">
Full article ">Figure 1
<p>Various phases of carbon nitride (CN).</p> Full article ">Figure 2
<p>g-C<sub>3</sub>N<sub>4</sub>: Electronic structure (<b>a</b>); Band gap (<b>b</b>); 2D representation with C and N (<b>c</b>).</p> Full article ">Figure 3
<p>Bulk g-C<sub>3</sub>N<sub>4</sub> from a different precursor material.</p> Full article ">Figure 4
<p>Morphology of g-C<sub>3</sub>N<sub>4</sub>.</p> Full article ">Figure 5
<p>Synthesis routes of g-C<sub>3</sub>N<sub>4</sub>.</p> Full article ">Figure 6
<p>Electrochemical sensing of various biomarkers.</p> Full article ">
Open AccessArticle
Effect of Synthesis Conditions on the Structure and Electrochemical Properties of Vertically Aligned Graphene/Carbon Nanofiber Hybrids
by
Mahnoosh Khosravifar, Kinshuk Dasgupta and Vesselin Shanov
C 2024, 10(4), 97; https://doi.org/10.3390/c10040097 - 24 Nov 2024
Abstract
In recent years, significant efforts have been dedicated to understanding the growth mechanisms behind the synthesis of vertically aligned nanocarbon structures using plasma-enhanced chemical vapor deposition (PECVD). This study explores how varying synthesis conditions, specifically hydrocarbon flow rate, hydrocarbon type, and plasma power,—affect
[...] Read more.
In recent years, significant efforts have been dedicated to understanding the growth mechanisms behind the synthesis of vertically aligned nanocarbon structures using plasma-enhanced chemical vapor deposition (PECVD). This study explores how varying synthesis conditions, specifically hydrocarbon flow rate, hydrocarbon type, and plasma power,—affect the microstructure, properties, and electrochemical performance of nitrogen-doped vertically aligned graphene (NVG) and nitrogen-doped vertically aligned carbon nanofibers (NVCNFs) hybrids. It was observed that adjustments in these synthesis parameters led to noticeable changes in the microstructure, with particularly significant alterations when changing the hydrocarbon precursor from acetylene to methane. The electrochemical investigation revealed that the sample synthesized at higher plasma power exhibited enhanced electron transfer kinetics, likely due to the higher density of open edges and nitrogen doping level. This study contributes to better understanding the PECVD process for fabricating nanocarbon materials, particularly for sensor applications.
Full article
(This article belongs to the Special Issue Carbon Functionalization: From Synthesis to Applications)
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Figure 1
Figure 1
<p>FESEM images of (<b>a</b>) AH15; (<b>b</b>) AH7; (<b>c</b>) AH15-160; and (<b>d</b>) MH15. Details about the growth conditions of the imaged samples are given in <a href="#carbon-10-00097-t001" class="html-table">Table 1</a>.</p> Full article ">Figure 2
<p>XPS spectrum of C1s for (<b>a</b>) AH7, (<b>c</b>) AH15-160, and (<b>e</b>) MH15; XPS spectrum of N1s for (<b>b</b>) AH7, (<b>d</b>) AH15-160, and (<b>f</b>) MH15. Gray and red lines represent the experimental and fitted curves, respectively.</p> Full article ">Figure 3
<p>Raman spectrum of (<b>a</b>) AH15, (<b>b</b>) AH7, (<b>c</b>) AH15-160, and (<b>d</b>) MH15.</p> Full article ">Figure 4
<p>(<b>a</b>) CV response of all the hybrid samples in 5 mM RuHex containing 0.5 M KCl at 10 mV/s scan rate, (<b>b</b>) CV curves of AH15-160 at scan rates of 5–200 mV/s, (<b>c</b>) peak current versus ν<sup>1/2</sup> for AH15-160 hybrid where ν<sup>1/2</sup> is the square root of the scan rate, i<sub>pa</sub> and i<sub>pc</sub> are the peak anodic and cathodic currents, respectively, and (<b>d</b>) SWASV response of AH15-160 in 0.1 M acetate buffer solution containing various Pb<sup>2+</sup> concentrations from 5 ppb to 35 ppb.</p> Full article ">
<p>FESEM images of (<b>a</b>) AH15; (<b>b</b>) AH7; (<b>c</b>) AH15-160; and (<b>d</b>) MH15. Details about the growth conditions of the imaged samples are given in <a href="#carbon-10-00097-t001" class="html-table">Table 1</a>.</p> Full article ">Figure 2
<p>XPS spectrum of C1s for (<b>a</b>) AH7, (<b>c</b>) AH15-160, and (<b>e</b>) MH15; XPS spectrum of N1s for (<b>b</b>) AH7, (<b>d</b>) AH15-160, and (<b>f</b>) MH15. Gray and red lines represent the experimental and fitted curves, respectively.</p> Full article ">Figure 3
<p>Raman spectrum of (<b>a</b>) AH15, (<b>b</b>) AH7, (<b>c</b>) AH15-160, and (<b>d</b>) MH15.</p> Full article ">Figure 4
<p>(<b>a</b>) CV response of all the hybrid samples in 5 mM RuHex containing 0.5 M KCl at 10 mV/s scan rate, (<b>b</b>) CV curves of AH15-160 at scan rates of 5–200 mV/s, (<b>c</b>) peak current versus ν<sup>1/2</sup> for AH15-160 hybrid where ν<sup>1/2</sup> is the square root of the scan rate, i<sub>pa</sub> and i<sub>pc</sub> are the peak anodic and cathodic currents, respectively, and (<b>d</b>) SWASV response of AH15-160 in 0.1 M acetate buffer solution containing various Pb<sup>2+</sup> concentrations from 5 ppb to 35 ppb.</p> Full article ">
Open AccessArticle
Kinetics of Thermal Decomposition of Carbon Nanotubes Decorated with Magnetite Nanoparticles
by
Rubén H. Olcay, Elia G. Palacios, Iván A. Reyes, Laura García-Hernández, Pedro A. Ramírez-Ortega, Sayra Ordoñez, Julio C. Juárez, Martín Reyes, Juan-Carlos González-Islas and Mizraim U. Flores
C 2024, 10(4), 96; https://doi.org/10.3390/c10040096 - 15 Nov 2024
Abstract
Magnetite nanoparticles were synthesized using the green chemistry technique; ferric chloride was used as a precursor agent and Moringa oleifera extract was used as a stabilizer agent. A black powder, characteristic of magnetite, was obtained. X-ray diffraction was performed on the synthesis product
[...] Read more.
Magnetite nanoparticles were synthesized using the green chemistry technique; ferric chloride was used as a precursor agent and Moringa oleifera extract was used as a stabilizer agent. A black powder, characteristic of magnetite, was obtained. X-ray diffraction was performed on the synthesis product and identified as magnetite (Fe3O4). Scanning electron microscopy characterization shows that nanoparticles have a spherical morphology, with sizes ranging from 15 nm to 35 nm. The synthesis of carbon nanotubes was carried out by the pyrolytic chemical deposition technique, from which multiwalled carbon nanotubes were obtained with diameters of 15–35 nm and of varied length. The decoration was carried out using the wet and sonification technique, where a non-homogeneous coating was obtained around the nanotubes. The thermal decomposition for both decorated and undecorated nanotubes presents two mass losses but with different slopes, where the activation energy for the decorated carbon nanotubes was 79.54 kJ/mol, which shows that the decoration gives more stability to the nanotubes since the activation energy of the undecorated nanotubes is 25.74 kJ/mol.
Full article
(This article belongs to the Collection Novel Applications of Carbon Nanotube-Based Materials)
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<p>X-ray diffraction spectrum of carbon nanotubes.</p> Full article ">Figure 2
<p>X-ray diffraction spectrum of magnetite particles.</p> Full article ">Figure 3
<p>SEM images of (<b>a</b>) the nanoparticles with diameters of 30 nanoparticles with diameters of 30 nm; (<b>b</b>) carbon nanotubes with diameters of 25 nm; (<b>c</b>) carbon nanotubes decorated with the magnetite nanoparticles viewed at 50,000X; (<b>d</b>) carbon nanotubes decorated with the magnetite nanoparticles viewed at 100,000X.</p> Full article ">Figure 4
<p>X-ray diffraction spectrum of carbon nanotubes decorated with magnetite nanoparticles.</p> Full article ">Figure 5
<p>(<b>a</b>) Differential thermogravimetric analysis of carbon nanotubes; (<b>b</b>) differential thermogravimetric analysis of magnetite nanoparticles; (<b>c</b>) differential thermogravimetric analysis of carbon nanotubes decorated with magnetite nanoparticles.</p> Full article ">Figure 6
<p>Kinetic analysis of thermal decomposition of carbon nanotubes. (<b>a</b>) First-stage mass loss isotherms; (<b>b</b>) calculation of the first-stage activation energy; (<b>c</b>) second-stage mass loss isotherms; (<b>d</b>) calculation of the second-stage activation energy.</p> Full article ">Figure 7
<p>Kinetic analysis of thermal decomposition of carbon nanotubes decorated with magnetite nanoparticles. (<b>a</b>) First-stage mass loss isotherms of carbon nanotubes decorated with magnetite nanoparticles; (<b>b</b>) calculation of the first-stage activation energy of carbon nanotubes decorated with magnetite nanoparticles; (<b>c</b>) second-stage mass loss isotherms of carbon nanotubes decorated with magnetite nanoparticles; (<b>d</b>) calculation of the second-stage activation energy of carbon nanotubes decorated with magnetite nanoparticles.</p> Full article ">Scheme 1
<p>Methodology for the synthesis of carbon nanotubes.</p> Full article ">
Full article ">Figure 1
<p>X-ray diffraction spectrum of carbon nanotubes.</p> Full article ">Figure 2
<p>X-ray diffraction spectrum of magnetite particles.</p> Full article ">Figure 3
<p>SEM images of (<b>a</b>) the nanoparticles with diameters of 30 nanoparticles with diameters of 30 nm; (<b>b</b>) carbon nanotubes with diameters of 25 nm; (<b>c</b>) carbon nanotubes decorated with the magnetite nanoparticles viewed at 50,000X; (<b>d</b>) carbon nanotubes decorated with the magnetite nanoparticles viewed at 100,000X.</p> Full article ">Figure 4
<p>X-ray diffraction spectrum of carbon nanotubes decorated with magnetite nanoparticles.</p> Full article ">Figure 5
<p>(<b>a</b>) Differential thermogravimetric analysis of carbon nanotubes; (<b>b</b>) differential thermogravimetric analysis of magnetite nanoparticles; (<b>c</b>) differential thermogravimetric analysis of carbon nanotubes decorated with magnetite nanoparticles.</p> Full article ">Figure 6
<p>Kinetic analysis of thermal decomposition of carbon nanotubes. (<b>a</b>) First-stage mass loss isotherms; (<b>b</b>) calculation of the first-stage activation energy; (<b>c</b>) second-stage mass loss isotherms; (<b>d</b>) calculation of the second-stage activation energy.</p> Full article ">Figure 7
<p>Kinetic analysis of thermal decomposition of carbon nanotubes decorated with magnetite nanoparticles. (<b>a</b>) First-stage mass loss isotherms of carbon nanotubes decorated with magnetite nanoparticles; (<b>b</b>) calculation of the first-stage activation energy of carbon nanotubes decorated with magnetite nanoparticles; (<b>c</b>) second-stage mass loss isotherms of carbon nanotubes decorated with magnetite nanoparticles; (<b>d</b>) calculation of the second-stage activation energy of carbon nanotubes decorated with magnetite nanoparticles.</p> Full article ">Scheme 1
<p>Methodology for the synthesis of carbon nanotubes.</p> Full article ">
Open AccessArticle
Preferential Stripping Analysis of Post-Transition Metals (In and Ga) at Bi/Hg Films Electroplated on Graphene-Functionalized Graphite Rods
by
Nastaran Ghaffari, Nazeem Jahed, Zareenah Abader, Priscilla G. L. Baker and Keagan Pokpas
C 2024, 10(4), 95; https://doi.org/10.3390/c10040095 - 12 Nov 2024
Abstract
In this study, we introduce a novel electrochemical sensor combining reduced graphene oxide (rGO) sheets with a bismuth–mercury (Bi/Hg) film, electroplated onto pencil graphite electrodes (PGEs) for the high-sensitivity detection of trace amounts of gallium (Ga3+) and indium (In3+)
[...] Read more.
In this study, we introduce a novel electrochemical sensor combining reduced graphene oxide (rGO) sheets with a bismuth–mercury (Bi/Hg) film, electroplated onto pencil graphite electrodes (PGEs) for the high-sensitivity detection of trace amounts of gallium (Ga3+) and indium (In3+) in water samples using square wave anodic stripping voltammetry (SWASV). The electrochemical modification of PGEs with rGO and bimetallic Bi/Hg films (ERGO-Bi/HgF-PGE) exhibited synergistic effects, enhancing the oxidation signals of Ga and In. Graphene oxide (GO) was accumulated onto PGEs and reduced through cyclic reduction. Key parameters influencing the electroanalytical performance, such as deposition potential, deposition time, and pH, were systematically optimized. The improved adsorption of Ga3+ and In3+ ions at the Bi/Hg films on the graphene-functionalized electrodes during the preconcentration step significantly enhanced sensitivity, achieving detection limits of 2.53 nmol L−1 for Ga3+ and 7.27 nmol L−1 for In3+. The preferential accumulation of each post-transition metal, used in transparent displays, to form fused alloys at Bi and Hg films, respectively, is highlighted. The sensor demonstrated effective quantification of Ga3+ and In3+ in tap water, with detection capabilities well below the USEPA guidelines. This study pioneers the use of bimetallic films to selectively and simultaneously detect the post-transition metals In3+ and Ga3+, highlighting the role of graphene functionalization in augmenting metal film accumulation on cost-effective graphite rods. Additionally, the combined synergistic effects of Bi/Hg and graphene functionalization have been explored for the first time, offering promising implications for environmental analysis and water quality monitoring.
Full article
(This article belongs to the Special Issue Carbon and Related Composites for Sensors and Energy Storage: Synthesis, Properties, and Application)
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<p>(<b>a</b>) Comparative CV voltammograms of bare PGE (black) and ERGO-PGE (red) recorded in 5 mM [Fe(CN) <sub>6</sub>]<sup>3−/4−</sup> with 0.1 M KCl as supporting electrolyte. Inset: HRTEM images of ERGO-nanoplatelets deposited on PGE surfaces. (<b>b</b>) Scan rate dependence (10 to 100 mV s<sup>−1</sup>) of ERGO-PGE recorded in the presence of redox probe and inset of the recorded currents vs. square root of scan rate. (<b>c</b>) SWASV voltammograms of 20 ppb Ga<sup>3+</sup> and 20 ppb In<sup>3+</sup> in 0.1 M acetate buffer solution (pH: 4.38) at ERGO-Bi/HgF-PGE with different numbers of GO deposition cycles from 1 to 9 cycles. (<b>d</b>) Corresponding plot of the effect of ERGO reduction cycles on peak currents of Ga<sup>3+</sup> and In<sup>3+</sup> at the ERGO-Bi/HgF-PGE in 0.1 M acetate buffer solution (pH 4.38).</p> Full article ">Figure 2
<p>(<b>a</b>) The comparison of SWASV measurements of 0.1 mol L<sup>−1</sup> ABS at pH 4.38 containing 30 ppb Ga<sup>3+</sup> and 20 ppb In<sup>3+</sup> at bare PGE, ERGO-PGE and ERGO-Bi/HgF-PGE. (<b>b</b>) Schematic illustration of anodic stripping voltammetry detection of In<sup>3+</sup> and Ga<sup>3+</sup>.</p> Full article ">Figure 3
<p>Effect of (<b>a</b>) electrochemically cleaning time (60–300 s), (<b>b</b>) pH (4.1–4.6), and (<b>c</b>) deposition potential (−1 to −1.7 V (vs. Ag/AgCl sat)) on the oxidation peak currents of Ga<sup>3+</sup> and In<sup>3+</sup> at the ERGO-Bi/HgF-PGE in a 0.1 M ABS (pH 4.38) containing 10 ppb Ga<sup>3+</sup> and 2 ppb In<sup>3+</sup>.</p> Full article ">Figure 4
<p>The effect of (<b>a</b>) Ga<sup>3+</sup> concentration, and (<b>b</b>) In<sup>3+</sup> concentration on Hg and Bi film formation.</p> Full article ">Figure 5
<p>Voltammograms and corresponding scatter plots of Ga<sup>3+</sup> and In<sup>3+</sup> at the ERGO-Bi/HgF-PGE in 0.1 M acetate buffer (pH 4.38) with (<b>a</b>,<b>b</b>) 80 ppb In<sup>3+</sup> concentration and Ga<sup>3+</sup> concentration varied between 0 ppb to 60 ppb, and (<b>c</b>,<b>d</b>) 70 ppb Ga<sup>3+</sup> concentration and In<sup>3+</sup> concentration varied between 0 ppb and 70 ppb.</p> Full article ">Figure 6
<p>SWAS voltammograms of the individual analysis of (<b>a</b>) Ga<sup>3+</sup> between 30 and 70 ppb and (<b>b</b>) In<sup>3+</sup> between 30 and 80 ppb recorded at ERGO-Bi/HgF-PGE, under optimized parameters. The corresponding calibration curves are shown as insets.</p> Full article ">Figure 7
<p>(<b>a</b>) SWAS voltammograms, and (<b>b</b>) corresponding calibration curves for ERGO-Bi/Hg-Film-PGE, with the optimized parameters (<b>a</b>). The Ga<sup>3+</sup> concentrations range from 30 µmol L<sup>−1</sup> to 80 ppb and the In<sup>3+</sup> concentrations range from 20 to 70 ppb.</p> Full article ">Figure 8
<p>Analysis of 2 ppb of (<b>a</b>) Ga<sup>3+</sup> and (<b>b</b>) In<sup>3+</sup> in tap water (pH 4.38). The recorded voltammograms and standard addition plots are provided.</p> Full article ">Figure 9
<p>Voltammograms and standard addition plots observed for the simultaneous detection of 2 ppb of In<sup>3+</sup> and 10 ppb Ga<sup>3+</sup> in tap water.</p> Full article ">Scheme 1
<p>Schematic illustration of the preferential stripping analysis of post-transition metals (In and Ga) at Bi/Hg films electroplated on graphene-functionalized graphite rods. Typically, electrochemically reduced graphene oxide (ERGO) nanoplatelets were electrochemically deposited on graphitic rods through successive fixed potential (−1.4 V, vs. Ag/AgCl sat) and cyclic reduction (five cycles) before the electroplating of bimetallic Bi/Hg-films. The ERGO-Bi/Hg-film-functionalized PGEs were then applied to the stripping analysis of In<sup>3+</sup> and Ga<sup>3+</sup> in wastewater samples.</p> Full article ">
Full article ">Figure 1
<p>(<b>a</b>) Comparative CV voltammograms of bare PGE (black) and ERGO-PGE (red) recorded in 5 mM [Fe(CN) <sub>6</sub>]<sup>3−/4−</sup> with 0.1 M KCl as supporting electrolyte. Inset: HRTEM images of ERGO-nanoplatelets deposited on PGE surfaces. (<b>b</b>) Scan rate dependence (10 to 100 mV s<sup>−1</sup>) of ERGO-PGE recorded in the presence of redox probe and inset of the recorded currents vs. square root of scan rate. (<b>c</b>) SWASV voltammograms of 20 ppb Ga<sup>3+</sup> and 20 ppb In<sup>3+</sup> in 0.1 M acetate buffer solution (pH: 4.38) at ERGO-Bi/HgF-PGE with different numbers of GO deposition cycles from 1 to 9 cycles. (<b>d</b>) Corresponding plot of the effect of ERGO reduction cycles on peak currents of Ga<sup>3+</sup> and In<sup>3+</sup> at the ERGO-Bi/HgF-PGE in 0.1 M acetate buffer solution (pH 4.38).</p> Full article ">Figure 2
<p>(<b>a</b>) The comparison of SWASV measurements of 0.1 mol L<sup>−1</sup> ABS at pH 4.38 containing 30 ppb Ga<sup>3+</sup> and 20 ppb In<sup>3+</sup> at bare PGE, ERGO-PGE and ERGO-Bi/HgF-PGE. (<b>b</b>) Schematic illustration of anodic stripping voltammetry detection of In<sup>3+</sup> and Ga<sup>3+</sup>.</p> Full article ">Figure 3
<p>Effect of (<b>a</b>) electrochemically cleaning time (60–300 s), (<b>b</b>) pH (4.1–4.6), and (<b>c</b>) deposition potential (−1 to −1.7 V (vs. Ag/AgCl sat)) on the oxidation peak currents of Ga<sup>3+</sup> and In<sup>3+</sup> at the ERGO-Bi/HgF-PGE in a 0.1 M ABS (pH 4.38) containing 10 ppb Ga<sup>3+</sup> and 2 ppb In<sup>3+</sup>.</p> Full article ">Figure 4
<p>The effect of (<b>a</b>) Ga<sup>3+</sup> concentration, and (<b>b</b>) In<sup>3+</sup> concentration on Hg and Bi film formation.</p> Full article ">Figure 5
<p>Voltammograms and corresponding scatter plots of Ga<sup>3+</sup> and In<sup>3+</sup> at the ERGO-Bi/HgF-PGE in 0.1 M acetate buffer (pH 4.38) with (<b>a</b>,<b>b</b>) 80 ppb In<sup>3+</sup> concentration and Ga<sup>3+</sup> concentration varied between 0 ppb to 60 ppb, and (<b>c</b>,<b>d</b>) 70 ppb Ga<sup>3+</sup> concentration and In<sup>3+</sup> concentration varied between 0 ppb and 70 ppb.</p> Full article ">Figure 6
<p>SWAS voltammograms of the individual analysis of (<b>a</b>) Ga<sup>3+</sup> between 30 and 70 ppb and (<b>b</b>) In<sup>3+</sup> between 30 and 80 ppb recorded at ERGO-Bi/HgF-PGE, under optimized parameters. The corresponding calibration curves are shown as insets.</p> Full article ">Figure 7
<p>(<b>a</b>) SWAS voltammograms, and (<b>b</b>) corresponding calibration curves for ERGO-Bi/Hg-Film-PGE, with the optimized parameters (<b>a</b>). The Ga<sup>3+</sup> concentrations range from 30 µmol L<sup>−1</sup> to 80 ppb and the In<sup>3+</sup> concentrations range from 20 to 70 ppb.</p> Full article ">Figure 8
<p>Analysis of 2 ppb of (<b>a</b>) Ga<sup>3+</sup> and (<b>b</b>) In<sup>3+</sup> in tap water (pH 4.38). The recorded voltammograms and standard addition plots are provided.</p> Full article ">Figure 9
<p>Voltammograms and standard addition plots observed for the simultaneous detection of 2 ppb of In<sup>3+</sup> and 10 ppb Ga<sup>3+</sup> in tap water.</p> Full article ">Scheme 1
<p>Schematic illustration of the preferential stripping analysis of post-transition metals (In and Ga) at Bi/Hg films electroplated on graphene-functionalized graphite rods. Typically, electrochemically reduced graphene oxide (ERGO) nanoplatelets were electrochemically deposited on graphitic rods through successive fixed potential (−1.4 V, vs. Ag/AgCl sat) and cyclic reduction (five cycles) before the electroplating of bimetallic Bi/Hg-films. The ERGO-Bi/Hg-film-functionalized PGEs were then applied to the stripping analysis of In<sup>3+</sup> and Ga<sup>3+</sup> in wastewater samples.</p> Full article ">
Open AccessArticle
Towards Photothermal Acid Catalysts Using Eco-Sustainable Sulfonated Carbon Nanoparticles—Part II: Thermal and Photothermal Catalysis of Biodiesel Synthesis
by
María Paula Militello, Luciano Tamborini, Diego F. Acevedo and Cesar A. Barbero
C 2024, 10(4), 94; https://doi.org/10.3390/c10040094 - 4 Nov 2024
Abstract
The main goal of this work is to evaluate the ability of sulfonated carbon nanoparticles (SCNs) to induce photothermal catalysis of the biodiesel synthesis reaction (transesterification of natural triglycerides (TGs) with alcohols). Carbon nanoparticles (CNs) are produced by the carbonization of cross-linked resin
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The main goal of this work is to evaluate the ability of sulfonated carbon nanoparticles (SCNs) to induce photothermal catalysis of the biodiesel synthesis reaction (transesterification of natural triglycerides (TGs) with alcohols). Carbon nanoparticles (CNs) are produced by the carbonization of cross-linked resin nanoparticles (RNs). The RNs are produced by condensation of a phenol (resorcinol or natural tannin) with formaldehyde under ammonia catalysis (Stober method). The method produces nanoparticles, which are carbonized into carbon nanoparticles (CNs). The illumination of CNs increases the temperature proportionally (linear) to the nanoparticle concentration and exposure time (with saturation). Solid acid catalysts are made by heating in concentrated sulfuric acid (SEAr sulfonation). The application of either light or a catalyst (SCNs) (at 25 °C) induced low conversions (<10%) for the esterification reaction of acetic acid with bioethanol. In contrast, the illumination of the reaction medium containing SCNs induced high conversions (>75%). In the case of biodiesel synthesis (transesterification of sunflower oil with bioethanol), conversions greater than 40% were observed only when light and the catalyst (SCNs) were applied simultaneously. Therefore, it is possible to use sulfonated carbon nanoparticles as photothermally activated catalysts for Fischer esterification and triglyceride transesterification (biodiesel synthesis).
Full article
(This article belongs to the Special Issue Carbons for Health and Environmental Protection (2nd Edition))
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<p>Photographs of carbon nanoparticle (CRF-6/600) dispersions in water at different concentrations (% <span class="html-italic">p</span>/<span class="html-italic">v</span>). Volume = 1 mL.</p> Full article ">Figure 2
<p>Dependence of temperature on time (<b>A</b>) and concentration (<b>B</b>) of CRF-6/600 in dispersions in water irradiated with NIR laser—laser power: 100 mW; λ = 780 nm; volume of dispersions = 1 mL.</p> Full article ">Figure 3
<p>Dependence of temperature on time (<b>A</b>) and concentration of (<b>B</b>) CRF-6/600 in dispersions in ethanol irradiated with NIR laser—laser power: 100 mW; λ = 780 nm; volume of dispersions = 1 mL.</p> Full article ">Figure 4
<p>Temperature dependence on the concentration of CRF-6/600, dispersed in methanol and water—volume = 1 mL; irradiation time = 30 s.</p> Full article ">Figure 5
<p>Dependence of the yield of fatty acid ethyl esters on the reaction temperature (Arrhenius plot) in the transesterification of sunflower oil with ethanol. Catalyst used: CRF 6/600/H<sub>2</sub>SO<sub>4</sub>/80; mass percentage of catalyst with respect to oil: 10%; oil/alcohol molar ratio: 1:20; reaction time: 5 h.</p> Full article ">Figure 6
<p>Dependence of the yield of ethyl esters with the molar ratio of ethanol/oil reagents in the transesterification of sunflower oil with ethanol. Catalyst used: CRF 6/600/H<sub>2</sub>SO<sub>4</sub>/80; temperature: 90 °C; mass percentage of catalyst with respect to oil: 10%; reaction time: 5 h.</p> Full article ">Figure 7
<p>Comparison of the transesterification yield using sulfonated carbon nanoparticles (produced from RF and TF resin nanoparticles) with commercial (Amberlite<sup>®</sup> and Nafion<sup>®</sup>) materials and sulfonated mesoporous silica (SBA15-S and SBA15-RF-S) [<a href="#B46-carbon-10-00094" class="html-bibr">46</a>].</p> Full article ">Figure 8
<p>Demonstration of the effect of photothermal catalysis on esterification: 0.1% <span class="html-italic">w</span>/<span class="html-italic">v</span> of CRF 6/600/H<sub>2</sub>SO<sub>4</sub>/80 as catalyst—acetic acid/ethanol volumetric ratio = 2. Source: sodium vapor lamp (λ = 589 nm, power = 525 W/m<sup>2</sup>, distance from source = 40 cm). Irradiation time = 25 min.</p> Full article ">Figure 9
<p>Demonstration of the effect of photothermal catalysis in transesterification: 10% <span class="html-italic">w</span>/<span class="html-italic">w</span> with respect to sunflower oil of CRF-6/600/H<sub>2</sub>SO<sub>4</sub>/80 as catalyst—oil/EtOH molar ratio = 1:20. Source: sodium vapor lamp (λ = 589 nm, power = 525 W/m<sup>2</sup>, distance from the source = 40 cm).</p> Full article ">Scheme 1
<p>Trans-esterification reaction of sunflower oil with bioethanol.</p> Full article ">
Full article ">Figure 1
<p>Photographs of carbon nanoparticle (CRF-6/600) dispersions in water at different concentrations (% <span class="html-italic">p</span>/<span class="html-italic">v</span>). Volume = 1 mL.</p> Full article ">Figure 2
<p>Dependence of temperature on time (<b>A</b>) and concentration (<b>B</b>) of CRF-6/600 in dispersions in water irradiated with NIR laser—laser power: 100 mW; λ = 780 nm; volume of dispersions = 1 mL.</p> Full article ">Figure 3
<p>Dependence of temperature on time (<b>A</b>) and concentration of (<b>B</b>) CRF-6/600 in dispersions in ethanol irradiated with NIR laser—laser power: 100 mW; λ = 780 nm; volume of dispersions = 1 mL.</p> Full article ">Figure 4
<p>Temperature dependence on the concentration of CRF-6/600, dispersed in methanol and water—volume = 1 mL; irradiation time = 30 s.</p> Full article ">Figure 5
<p>Dependence of the yield of fatty acid ethyl esters on the reaction temperature (Arrhenius plot) in the transesterification of sunflower oil with ethanol. Catalyst used: CRF 6/600/H<sub>2</sub>SO<sub>4</sub>/80; mass percentage of catalyst with respect to oil: 10%; oil/alcohol molar ratio: 1:20; reaction time: 5 h.</p> Full article ">Figure 6
<p>Dependence of the yield of ethyl esters with the molar ratio of ethanol/oil reagents in the transesterification of sunflower oil with ethanol. Catalyst used: CRF 6/600/H<sub>2</sub>SO<sub>4</sub>/80; temperature: 90 °C; mass percentage of catalyst with respect to oil: 10%; reaction time: 5 h.</p> Full article ">Figure 7
<p>Comparison of the transesterification yield using sulfonated carbon nanoparticles (produced from RF and TF resin nanoparticles) with commercial (Amberlite<sup>®</sup> and Nafion<sup>®</sup>) materials and sulfonated mesoporous silica (SBA15-S and SBA15-RF-S) [<a href="#B46-carbon-10-00094" class="html-bibr">46</a>].</p> Full article ">Figure 8
<p>Demonstration of the effect of photothermal catalysis on esterification: 0.1% <span class="html-italic">w</span>/<span class="html-italic">v</span> of CRF 6/600/H<sub>2</sub>SO<sub>4</sub>/80 as catalyst—acetic acid/ethanol volumetric ratio = 2. Source: sodium vapor lamp (λ = 589 nm, power = 525 W/m<sup>2</sup>, distance from source = 40 cm). Irradiation time = 25 min.</p> Full article ">Figure 9
<p>Demonstration of the effect of photothermal catalysis in transesterification: 10% <span class="html-italic">w</span>/<span class="html-italic">w</span> with respect to sunflower oil of CRF-6/600/H<sub>2</sub>SO<sub>4</sub>/80 as catalyst—oil/EtOH molar ratio = 1:20. Source: sodium vapor lamp (λ = 589 nm, power = 525 W/m<sup>2</sup>, distance from the source = 40 cm).</p> Full article ">Scheme 1
<p>Trans-esterification reaction of sunflower oil with bioethanol.</p> Full article ">
Open AccessArticle
Fabrication of Cu-Doped Diamond-like Carbon Film for Improving Sealing Performance of Hydraulic Cylinder of Shearers
by
Yanrong Yang, Xiang Yu, Zhiyan Zhao and Lei Zhang
C 2024, 10(4), 93; https://doi.org/10.3390/c10040093 - 30 Oct 2024
Abstract
During shearer operation, the piston rod is susceptible to wear from the invasion of pollutants, thus ruining the sealing ring in the hydraulic cylinder. This work attempts to conduct a systematic investigation of Cu-doped diamond-like carbon (Cu-DLC) film to improve the seal performance.
[...] Read more.
During shearer operation, the piston rod is susceptible to wear from the invasion of pollutants, thus ruining the sealing ring in the hydraulic cylinder. This work attempts to conduct a systematic investigation of Cu-doped diamond-like carbon (Cu-DLC) film to improve the seal performance. The failure process of the cylinder was analyzed, and relevant parameters were determined. Several Cu-DLC films were deposited on the substrate of the piston rod in a multi-ion beam-assisted system, and their structures and combined tribological performances were investigated. The hardness of the film ranges from 27.6 GPa to 14.8 GPa, and the internal stress ranges from 3500 MPa to 1750 MPa. The steady-state frictional coefficient of the film ranges from 0.04 to 0.15; the wear rate decreases first and then increases, and it reaches its lowest (5.0 × 10−9 mm3/N·m) at 9.2 at.% content. a:C-Cu9.2% film presents optimal combined tribological performances in this experiment. The modification mechanism of Cu-DLC film for the seal performance may come from the synergistic effects of (i) the contact force and friction-heat-induced film graphitization, (ii) Cu doping improves the toughness of the film and acts as a solid lubricant, and (iii) the transfer layer plays a role in self-lubrication.
Full article
(This article belongs to the Special Issue Micro/Nanofabrication of Carbon-Based Devices and Their Applications)
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<p>Structure diagram of a hydraulic cylinder of shearer: (1) guide ring; (2) seal ring; (3) piston rod; (4) rod chamber; (5) cylinder block; (6) piston; (7) nonrod chamber.</p> Full article ">Figure 2
<p>XRD spectra of Cu-DLC film with six Cu contents.</p> Full article ">Figure 3
<p>Hardness of Cu-DLC film with six Cu contents.</p> Full article ">Figure 4
<p>Variation in internal stress of Cu-DLC film with six Cu contents.</p> Full article ">Figure 5
<p>Friction coefficient of DLC Film with six Cu contents.</p> Full article ">Figure 6
<p>Wear rate of DLC films with different Cu content.</p> Full article ">Figure 7
<p>Photographs of wear scar morphology of a:C-Cu<sub>9.2%</sub> film during friction test: (<b>a</b>) 10 min/film; (<b>b</b>) 20 min/film; (<b>c</b>) 50 min/film; (<b>d</b>) 50 min/the ring.</p> Full article ">Figure 8
<p>SEM and local EDS mapping images of wear scar for a:C-Cu<sub>9.2%</sub> film: (<b>a</b>,<b>b</b>) SEM images; (<b>c</b>–<b>f</b>) EDS mapping images of C (<b>c</b>), Cu (<b>d</b>), Fe (<b>e</b>), and Cr (<b>f</b>).</p> Full article ">Figure 9
<p>Raman spectra of a:C-Cu<sub>0%</sub> and a:C-Cu<sub>9.2%</sub> film: (<b>a</b>) undoped DLC (a:C-Cu<sub>0%</sub>) film; a:C-Cu<sub>9.2%</sub> film (<b>b</b>) deposited film (No wear), (<b>c</b>) wear track (Track 5N), and (<b>d</b>) wear debris (Debris).</p> Full article ">Figure 10
<p>Core level XPS spectra of (<b>a</b>) C 1s and (<b>b</b>) Cu 2p of a:C-Cu<sub>9.2%</sub> film.</p> Full article ">Figure 11
<p>Mechanism of Cu-DLC film improving sealability of the hydraulic cylinders (<b>a</b>) schematic model; (<b>b</b>) section view of friction portion; (<b>c</b>) image of contact surfaces; (<b>d</b>) microscopic diagram of transfer layer.</p> Full article ">
Full article ">Figure 1
<p>Structure diagram of a hydraulic cylinder of shearer: (1) guide ring; (2) seal ring; (3) piston rod; (4) rod chamber; (5) cylinder block; (6) piston; (7) nonrod chamber.</p> Full article ">Figure 2
<p>XRD spectra of Cu-DLC film with six Cu contents.</p> Full article ">Figure 3
<p>Hardness of Cu-DLC film with six Cu contents.</p> Full article ">Figure 4
<p>Variation in internal stress of Cu-DLC film with six Cu contents.</p> Full article ">Figure 5
<p>Friction coefficient of DLC Film with six Cu contents.</p> Full article ">Figure 6
<p>Wear rate of DLC films with different Cu content.</p> Full article ">Figure 7
<p>Photographs of wear scar morphology of a:C-Cu<sub>9.2%</sub> film during friction test: (<b>a</b>) 10 min/film; (<b>b</b>) 20 min/film; (<b>c</b>) 50 min/film; (<b>d</b>) 50 min/the ring.</p> Full article ">Figure 8
<p>SEM and local EDS mapping images of wear scar for a:C-Cu<sub>9.2%</sub> film: (<b>a</b>,<b>b</b>) SEM images; (<b>c</b>–<b>f</b>) EDS mapping images of C (<b>c</b>), Cu (<b>d</b>), Fe (<b>e</b>), and Cr (<b>f</b>).</p> Full article ">Figure 9
<p>Raman spectra of a:C-Cu<sub>0%</sub> and a:C-Cu<sub>9.2%</sub> film: (<b>a</b>) undoped DLC (a:C-Cu<sub>0%</sub>) film; a:C-Cu<sub>9.2%</sub> film (<b>b</b>) deposited film (No wear), (<b>c</b>) wear track (Track 5N), and (<b>d</b>) wear debris (Debris).</p> Full article ">Figure 10
<p>Core level XPS spectra of (<b>a</b>) C 1s and (<b>b</b>) Cu 2p of a:C-Cu<sub>9.2%</sub> film.</p> Full article ">Figure 11
<p>Mechanism of Cu-DLC film improving sealability of the hydraulic cylinders (<b>a</b>) schematic model; (<b>b</b>) section view of friction portion; (<b>c</b>) image of contact surfaces; (<b>d</b>) microscopic diagram of transfer layer.</p> Full article ">
Open AccessReview
Advanced Graphene-Based Technologies for Antibiotic Removal from Wastewater: A Review (2016–2024)
by
Joydip Sengupta and Chaudhery Mustansar Hussain
C 2024, 10(4), 92; https://doi.org/10.3390/c10040092 - 15 Oct 2024
Abstract
The increasing presence of antibiotics in wastewater poses significant environmental risks, including the promotion of antibiotic resistance and harm to aquatic ecosystems. This study reviews advancements in graphene-based technologies for removing antibiotics from wastewater between 2016 and 2024. Graphene-based platforms, such as graphene
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The increasing presence of antibiotics in wastewater poses significant environmental risks, including the promotion of antibiotic resistance and harm to aquatic ecosystems. This study reviews advancements in graphene-based technologies for removing antibiotics from wastewater between 2016 and 2024. Graphene-based platforms, such as graphene oxide (GO), reduced graphene oxide (rGO), and graphene composites, have shown great promise in this field because of their exceptional adsorption capacities and rapid photocatalytic degradation capabilities. Functionalized graphene materials and graphene integrated with other substances, such as metal oxides and polymers, have enhanced performance in terms of antibiotic removal through mechanisms such as adsorption and photocatalysis. These technologies have been evaluated under various conditions, such as pH and temperature, demonstrating their practical applicability. Despite challenges related to scalability, cost-effectiveness, and environmental impact, the advancements in graphene-based technologies during this period highlight their significant potential for effective antibiotic removal, paving the way for safer and more sustainable environmental management practices.
Full article
(This article belongs to the Special Issue Carbon-Based Materials Applied in Water and Wastewater Treatment)
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>Graphene and its derivatives (reproduced with permission from [<a href="#B13-carbon-10-00092" class="html-bibr">13</a>]).</p> Full article ">Figure 2
<p>Different synthesis methods for graphene-based materials (reproduced with permission from [<a href="#B35-carbon-10-00092" class="html-bibr">35</a>]).</p> Full article ">Figure 3
<p>Different sources of antibiotics in wastewater.</p> Full article ">Figure 4
<p>Diagram depicting AMP wastewater treatment via the C<sub>3</sub>N<sub>4</sub>-MoS<sub>2</sub>/3DG flow-through system, enhanced by the addition of trace amounts of H<sub>2</sub>O<sub>2</sub> and electricity generation by the air cathode. (Reproduced with permission from [<a href="#B94-carbon-10-00092" class="html-bibr">94</a>]).</p> Full article ">Figure 5
<p>GO-based NM88B/GO/SA aerogels for antibiotic-contaminated wastewater (reproduced with permission from [<a href="#B95-carbon-10-00092" class="html-bibr">95</a>]).</p> Full article ">Figure 6
<p>A schematic of the experimental design included the following steps: (1) Synthesizing graphene oxide (GO) from raw graphite flakes via oxidation via a modified Hummers method. (2) Obtaining the resulting GO. (3) Copper oxide-doped reduced graphene oxide (CuO–rGO) was synthesized from synthesized GO and an aqueous CuSO<sub>4</sub>·5H<sub>2</sub>O solution, and (4) zinc oxide-doped reduced graphene oxide (ZnO–rGO) was synthesized from synthesized GO and an aqueous ZnSO<sub>4</sub>·7H<sub>2</sub>O solution through a series of thermal chemical reactions. (5) The chemical and physical properties of GO, CuO–rGO, and ZnO–rGO were characterized via standard microscopic and spectroscopic techniques, including SEM, TEM, ATR-FTIR, and XPS. (6) Batch adsorption experiments were conducted to remove textile dyes (rhodamine 6G (R-6G) and malachite green (MG)) and antibiotics (amoxicillin (AMOX) and tetracycline (TC)) from aqueous solutions via GO, CuO–rGO, and ZnO–rGO adsorbents, followed by analysis via UV–visible spectroscopy. (7) Mathematical modeling and kinetics were applied to study the batch adsorption of textile dyes (R-6G, MG) and antibiotics (AMOX, TC) on GO, CuO–rGO, and ZnO–rGO. (8) Analyzing functional group changes on the GO, CuO–rGO, and ZnO–rGO adsorbents after adsorption of the textile dyes and antibiotics via ATR-FTIR. (Reproduced with permission from [<a href="#B99-carbon-10-00092" class="html-bibr">99</a>]).</p> Full article ">Figure 7
<p>Diagrammatic representation of the synthesis process for free-standing graphene oxide (GO), Ti<sub>3</sub>C<sub>2</sub>Tx, and GO/Ti<sub>3</sub>C<sub>2</sub>Tx composite membranes (reproduced with permission from [<a href="#B101-carbon-10-00092" class="html-bibr">101</a>]).</p> Full article ">Figure 8
<p>Influence of various factors on the tetracycline adsorption efficiency of the Cu/PANI/GO nanocomposite: (<b>a</b>) pH and zeta potential, (<b>b</b>) mass dosage (mg), (<b>c</b>) presence of interfering ions, (<b>d</b>) synergistic impact of Cu nanoparticles and polyaniline on the adsorption efficiency, and (<b>e</b>) reusability of the Cu/PANI/GO nanocomposite over four consecutive cycles under optimal conditions (reproduced with permission from [<a href="#B102-carbon-10-00092" class="html-bibr">102</a>]).</p> Full article ">Figure 9
<p>Removal of norfloxacin (<b>A</b>), tetracycline (<b>B</b>), and flumequine (<b>C</b>) via activated inorganic peroxides with magnetic graphene MG0.2 (reproduced with permission from [<a href="#B88-carbon-10-00092" class="html-bibr">88</a>]).</p> Full article ">Scheme 1
<p>Three steps of this systematic literature review following PRISMA, 2020 [<a href="#B92-carbon-10-00092" class="html-bibr">92</a>].</p> Full article ">
Full article ">Figure 1
<p>Graphene and its derivatives (reproduced with permission from [<a href="#B13-carbon-10-00092" class="html-bibr">13</a>]).</p> Full article ">Figure 2
<p>Different synthesis methods for graphene-based materials (reproduced with permission from [<a href="#B35-carbon-10-00092" class="html-bibr">35</a>]).</p> Full article ">Figure 3
<p>Different sources of antibiotics in wastewater.</p> Full article ">Figure 4
<p>Diagram depicting AMP wastewater treatment via the C<sub>3</sub>N<sub>4</sub>-MoS<sub>2</sub>/3DG flow-through system, enhanced by the addition of trace amounts of H<sub>2</sub>O<sub>2</sub> and electricity generation by the air cathode. (Reproduced with permission from [<a href="#B94-carbon-10-00092" class="html-bibr">94</a>]).</p> Full article ">Figure 5
<p>GO-based NM88B/GO/SA aerogels for antibiotic-contaminated wastewater (reproduced with permission from [<a href="#B95-carbon-10-00092" class="html-bibr">95</a>]).</p> Full article ">Figure 6
<p>A schematic of the experimental design included the following steps: (1) Synthesizing graphene oxide (GO) from raw graphite flakes via oxidation via a modified Hummers method. (2) Obtaining the resulting GO. (3) Copper oxide-doped reduced graphene oxide (CuO–rGO) was synthesized from synthesized GO and an aqueous CuSO<sub>4</sub>·5H<sub>2</sub>O solution, and (4) zinc oxide-doped reduced graphene oxide (ZnO–rGO) was synthesized from synthesized GO and an aqueous ZnSO<sub>4</sub>·7H<sub>2</sub>O solution through a series of thermal chemical reactions. (5) The chemical and physical properties of GO, CuO–rGO, and ZnO–rGO were characterized via standard microscopic and spectroscopic techniques, including SEM, TEM, ATR-FTIR, and XPS. (6) Batch adsorption experiments were conducted to remove textile dyes (rhodamine 6G (R-6G) and malachite green (MG)) and antibiotics (amoxicillin (AMOX) and tetracycline (TC)) from aqueous solutions via GO, CuO–rGO, and ZnO–rGO adsorbents, followed by analysis via UV–visible spectroscopy. (7) Mathematical modeling and kinetics were applied to study the batch adsorption of textile dyes (R-6G, MG) and antibiotics (AMOX, TC) on GO, CuO–rGO, and ZnO–rGO. (8) Analyzing functional group changes on the GO, CuO–rGO, and ZnO–rGO adsorbents after adsorption of the textile dyes and antibiotics via ATR-FTIR. (Reproduced with permission from [<a href="#B99-carbon-10-00092" class="html-bibr">99</a>]).</p> Full article ">Figure 7
<p>Diagrammatic representation of the synthesis process for free-standing graphene oxide (GO), Ti<sub>3</sub>C<sub>2</sub>Tx, and GO/Ti<sub>3</sub>C<sub>2</sub>Tx composite membranes (reproduced with permission from [<a href="#B101-carbon-10-00092" class="html-bibr">101</a>]).</p> Full article ">Figure 8
<p>Influence of various factors on the tetracycline adsorption efficiency of the Cu/PANI/GO nanocomposite: (<b>a</b>) pH and zeta potential, (<b>b</b>) mass dosage (mg), (<b>c</b>) presence of interfering ions, (<b>d</b>) synergistic impact of Cu nanoparticles and polyaniline on the adsorption efficiency, and (<b>e</b>) reusability of the Cu/PANI/GO nanocomposite over four consecutive cycles under optimal conditions (reproduced with permission from [<a href="#B102-carbon-10-00092" class="html-bibr">102</a>]).</p> Full article ">Figure 9
<p>Removal of norfloxacin (<b>A</b>), tetracycline (<b>B</b>), and flumequine (<b>C</b>) via activated inorganic peroxides with magnetic graphene MG0.2 (reproduced with permission from [<a href="#B88-carbon-10-00092" class="html-bibr">88</a>]).</p> Full article ">Scheme 1
<p>Three steps of this systematic literature review following PRISMA, 2020 [<a href="#B92-carbon-10-00092" class="html-bibr">92</a>].</p> Full article ">
Open AccessArticle
Stacking Fault Nucleation in Films of Vertically Oriented Multiwall Carbon Nanotubes by Pyrolysis of Ferrocene and Dimethyl Ferrocene at a Low Vapor Flow Rate
by
Ayoub Taallah, Shanling Wang, Omololu Odunmbaku, Lin Zhang, Xilong Guo, Yixin Dai, Wenkang Li, Huanqing Ye, Hansong Wu, Jiaxin Song, Jian Guo, Jiqiu Wen, Yi He and Filippo S. Boi
C 2024, 10(4), 91; https://doi.org/10.3390/c10040091 - 12 Oct 2024
Abstract
Recent observations of superconductivity in low-dimensional systems composed of twisted, untwisted, or rhombohedral graphene have attracted significant attention. One-dimensional moiré superlattices and flat bands have interestingly been identified in collapsed chiral carbon nanotubes (CNTs), opening up new avenues for the tunability of the
[...] Read more.
Recent observations of superconductivity in low-dimensional systems composed of twisted, untwisted, or rhombohedral graphene have attracted significant attention. One-dimensional moiré superlattices and flat bands have interestingly been identified in collapsed chiral carbon nanotubes (CNTs), opening up new avenues for the tunability of the electronic properties in these systems. The nucleation of hexagonal moiré superlattices and other types of stacking faults has also been demonstrated in partially collapsed and uncollapsed carbon nano-onions (CNOs). Here, we report a novel investigation on the dynamics of stacking fault nucleation within the multilayered lattices of micrometer-scale vertically oriented films of multiwall CNTs (MWCNTs), resulting from the pyrolysis of molecular precursors consisting of ferrocene or dimethyl ferrocene, at low vapor flow rates of ~5–20 mL/min. Interestingly, local nucleation of moiré-like superlattices (as stacking faults) was found when employing dimethyl ferrocene as the pyrolysis precursor. The morphological and structural properties of these systems were investigated with the aid of scanning and transmission electron microscopies, namely SEM, TEM, and HRTEM, as well as X-ray diffraction (XRD) and Raman point/mapping spectroscopy. Deconvolution analyses of the Raman spectra also demonstrated a local surface oxidation, possibly occurring on defect-rich interfaces, frequently identified within or in proximity of bamboo-like graphitic caps. By employing high-temperature Raman spectroscopy, we demonstrate a post-growth re-graphitization, which may also be visualized as an alternative way of depleting the oxygen content within the MWCNTs’ interfaces through recrystallization.
Full article
(This article belongs to the Special Issue Characterization of Disorder in Carbons (2nd Edition))
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Figure 1
Figure 1
<p>Schematic of the CVD system employed for the nucleation and growth of VA-MWCNTs, employing ferrocene or dimethyl ferrocene as the molecular precursor.</p> Full article ">Figure 2
<p>SEM micrographs (<b>A</b>–<b>F</b>) of typical flakes of free-standing films of MWCNTs obtained by pyrolysis of dimethyl ferrocene at a low Ar vapor flow rate of ~10 mL/min. In particular, the micrographs in (<b>C</b>–<b>E</b>) allow for a clear observation of the high degree of CNT alignment.</p> Full article ">Figure 3
<p>Transmission electron micrographs (<b>A</b>–<b>F</b>) showing, with an increasing level of detail, the cross-sectional morphology of films comprising vertically aligned MWCNTs decorated with filled CNOs. The TEM micrographs in (<b>E</b>,<b>F</b>) show the fine details of the CNOs decorating the MWCNT (scale bar in green corresponds to 0.05 μm). These films were obtained through the pyrolysis of ferrocene at very low vapor flow rates of ~5 mL/min.</p> Full article ">Figure 4
<p>Low-magnification TEM micrograph of as-grown VA-MWCNTs obtained through the pyrolysis of dimethyl ferrocene.</p> Full article ">Figure 5
<p>HRTEM micrographs (<b>A</b>–<b>F</b>) exhibiting the structural arrangement of the CNT walls. Note the presence of structural stress and dislocation-rich interfaces, as shown in (<b>D</b>–<b>F</b>). The formation of graphitic caps on both sides of the encapsulated particle indicates a bamboo-like growth mechanism with a variable orientation. The presence of stacking faults and moiré-like super-periodicities is visible in the micrograph presented in (<b>D</b>).</p> Full article ">Figure 6
<p>HRTEM (<b>A</b>–<b>C</b>) and profile analyses (<b>D</b>) revealing the presence of a transition in the stacking order of the CNT walls in proximity of partially nucleated graphite caps (see (<b>B</b>)).</p> Full article ">Figure 7
<p>HRTEM micrograph revealing, with high detail, the nucleation of moiré-like stacking faults within the walls of the CNT, as a result of a variation in the orientation of the multilayered lattice. The nucleation of this type of stacking fault appears to be linked to the formation of graphitic bamboo-like caps with a variable orientation (see cyan arrow).</p> Full article ">Figure 8
<p>HRTEM micrograph of the stacking fault shown in <a href="#carbon-10-00091-f007" class="html-fig">Figure 7</a> (cyan arrow) and profile analyses (<b>A</b>–<b>C</b>) performed with the aid of DigitalMicrograph software, revealing examples of super-periodicities D ranging from ~0.4 nm to ~0.6 nm.</p> Full article ">Figure 9
<p>Typical XRD diffractogram (red line) and Rietveld refinement (green line) of the free-standing aligned MWCNT films, revealing the following phase abundances: 74.8% Fe<sub>3</sub>C, 18.6% α-Fe, and 6.6% γ-Fe. The magenta line corresponds to the difference between the XRD diffractogram (experimental data) and the Rietveld model (theoretical data). The extracted R<sub>p</sub> value was 0.0278. The following database cards were employed for the refinements: COD 1008725 (Fe<sub>3</sub>C with space group Pnma), COD 1100108 (α-Fe with space group Im-3m), and COD 1534888 (γ-Fe with space group Fm-3m). See ESI <a href="#app1-carbon-10-00091" class="html-app">Figure S3</a> for details on extracted unit cell parameters.</p> Full article ">Figure 10
<p>Typical examples of Raman spectroscopy point/map analyses of the VA-MWCNT. The map analyses in (<b>A</b>–<b>D</b>) and the point analyses in (<b>E</b>,<b>F</b>) highlight a significant local variation in the amplitude of the D and G band components, with the appearance of D’ band features indicative of an enhancement in the relative abundance of defect-rich carbon within certain regions of the film.</p> Full article ">Figure 11
<p>In (<b>A</b>,<b>B</b>) deconvolution analyses of the Raman spectra collected at T ~ 673 K after 1 min (<b>A</b>) and 2 min (<b>B</b>) of laser exposure, respectively, evidencing the presence of an enhanced 2D band in (<b>B</b>), deriving from a re-graphitization process.</p> Full article ">Figure 12
<p>High-temperature Raman spectroscopy measurement showing the variation in the intensities of D, G, and 2D bands as a function of laser beam exposure time for a constant temperature (T ~ 673 K under N<sub>2</sub> flow). This is shown in a large frequency range in (<b>A</b>), from 1000 to 3000 cm<sup>−1</sup> and shorter frequency range in (<b>B</b>,<b>C</b>) from 1000 to 1800 and from 1800 to 3000 cm<sup>−1</sup> respectively.</p> Full article ">Figure 13
<p>Evolution of the amplitude of the 2D band as a function of the laser beam exposure time, at T ~ 673 K.</p> Full article ">
<p>Schematic of the CVD system employed for the nucleation and growth of VA-MWCNTs, employing ferrocene or dimethyl ferrocene as the molecular precursor.</p> Full article ">Figure 2
<p>SEM micrographs (<b>A</b>–<b>F</b>) of typical flakes of free-standing films of MWCNTs obtained by pyrolysis of dimethyl ferrocene at a low Ar vapor flow rate of ~10 mL/min. In particular, the micrographs in (<b>C</b>–<b>E</b>) allow for a clear observation of the high degree of CNT alignment.</p> Full article ">Figure 3
<p>Transmission electron micrographs (<b>A</b>–<b>F</b>) showing, with an increasing level of detail, the cross-sectional morphology of films comprising vertically aligned MWCNTs decorated with filled CNOs. The TEM micrographs in (<b>E</b>,<b>F</b>) show the fine details of the CNOs decorating the MWCNT (scale bar in green corresponds to 0.05 μm). These films were obtained through the pyrolysis of ferrocene at very low vapor flow rates of ~5 mL/min.</p> Full article ">Figure 4
<p>Low-magnification TEM micrograph of as-grown VA-MWCNTs obtained through the pyrolysis of dimethyl ferrocene.</p> Full article ">Figure 5
<p>HRTEM micrographs (<b>A</b>–<b>F</b>) exhibiting the structural arrangement of the CNT walls. Note the presence of structural stress and dislocation-rich interfaces, as shown in (<b>D</b>–<b>F</b>). The formation of graphitic caps on both sides of the encapsulated particle indicates a bamboo-like growth mechanism with a variable orientation. The presence of stacking faults and moiré-like super-periodicities is visible in the micrograph presented in (<b>D</b>).</p> Full article ">Figure 6
<p>HRTEM (<b>A</b>–<b>C</b>) and profile analyses (<b>D</b>) revealing the presence of a transition in the stacking order of the CNT walls in proximity of partially nucleated graphite caps (see (<b>B</b>)).</p> Full article ">Figure 7
<p>HRTEM micrograph revealing, with high detail, the nucleation of moiré-like stacking faults within the walls of the CNT, as a result of a variation in the orientation of the multilayered lattice. The nucleation of this type of stacking fault appears to be linked to the formation of graphitic bamboo-like caps with a variable orientation (see cyan arrow).</p> Full article ">Figure 8
<p>HRTEM micrograph of the stacking fault shown in <a href="#carbon-10-00091-f007" class="html-fig">Figure 7</a> (cyan arrow) and profile analyses (<b>A</b>–<b>C</b>) performed with the aid of DigitalMicrograph software, revealing examples of super-periodicities D ranging from ~0.4 nm to ~0.6 nm.</p> Full article ">Figure 9
<p>Typical XRD diffractogram (red line) and Rietveld refinement (green line) of the free-standing aligned MWCNT films, revealing the following phase abundances: 74.8% Fe<sub>3</sub>C, 18.6% α-Fe, and 6.6% γ-Fe. The magenta line corresponds to the difference between the XRD diffractogram (experimental data) and the Rietveld model (theoretical data). The extracted R<sub>p</sub> value was 0.0278. The following database cards were employed for the refinements: COD 1008725 (Fe<sub>3</sub>C with space group Pnma), COD 1100108 (α-Fe with space group Im-3m), and COD 1534888 (γ-Fe with space group Fm-3m). See ESI <a href="#app1-carbon-10-00091" class="html-app">Figure S3</a> for details on extracted unit cell parameters.</p> Full article ">Figure 10
<p>Typical examples of Raman spectroscopy point/map analyses of the VA-MWCNT. The map analyses in (<b>A</b>–<b>D</b>) and the point analyses in (<b>E</b>,<b>F</b>) highlight a significant local variation in the amplitude of the D and G band components, with the appearance of D’ band features indicative of an enhancement in the relative abundance of defect-rich carbon within certain regions of the film.</p> Full article ">Figure 11
<p>In (<b>A</b>,<b>B</b>) deconvolution analyses of the Raman spectra collected at T ~ 673 K after 1 min (<b>A</b>) and 2 min (<b>B</b>) of laser exposure, respectively, evidencing the presence of an enhanced 2D band in (<b>B</b>), deriving from a re-graphitization process.</p> Full article ">Figure 12
<p>High-temperature Raman spectroscopy measurement showing the variation in the intensities of D, G, and 2D bands as a function of laser beam exposure time for a constant temperature (T ~ 673 K under N<sub>2</sub> flow). This is shown in a large frequency range in (<b>A</b>), from 1000 to 3000 cm<sup>−1</sup> and shorter frequency range in (<b>B</b>,<b>C</b>) from 1000 to 1800 and from 1800 to 3000 cm<sup>−1</sup> respectively.</p> Full article ">Figure 13
<p>Evolution of the amplitude of the 2D band as a function of the laser beam exposure time, at T ~ 673 K.</p> Full article ">
Open AccessArticle
Optimizing Graphene Oxide Film Quality: The Role of Solvent and Deposition Technique
by
Grazia Giuseppina Politano
C 2024, 10(4), 90; https://doi.org/10.3390/c10040090 - 10 Oct 2024
Abstract
Graphene oxide (GO) is a promising material due to its high mechanical strength, electrical conductivity, and optical transparency, making it suitable for applications like optoelectronics and energy storage. This study focuses on a simplified method of depositing and characterizing GO films via drop
[...] Read more.
Graphene oxide (GO) is a promising material due to its high mechanical strength, electrical conductivity, and optical transparency, making it suitable for applications like optoelectronics and energy storage. This study focuses on a simplified method of depositing and characterizing GO films via drop casting, particularly using isopropanol and water as solvents, and compares the results with reference samples of graphene produced by chemical vapor deposition (CVD) and GO films deposited by electrophoretic deposition (EPD). The optical properties of these films were analyzed using Variable Angle Spectroscopic Ellipsometry (VASE). The study revealed that GO films prepared with isopropanol exhibited a lower refractive index compared to those using water. Therefore, the research highlighted the significance of solvent choice and deposition method on the overall film quality. This work provides insights into optimizing GO film properties through careful solvent selection, contributing to the broader understanding and application of GO in advanced technologies.
Full article
(This article belongs to the Topic Application of Graphene-Based Materials, 2nd Edition)
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> for CVD graphene sample.</p> Full article ">Figure 2
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> for EPD-deposited sample of GO at concentration 0.25 mg/mL, time of deposition 1 min.</p> Full article ">Figure 3
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> for EPD GO sample after the annealing treatment at 400 °C for 1 h.</p> Full article ">Figure 4
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> for drop-casted sample of GO at concentration 0.1 mg/mL in water.</p> Full article ">Figure 5
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> of GO in isopropanol films (0.1 mg/mL).</p> Full article ">
Full article ">Figure 1
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> for CVD graphene sample.</p> Full article ">Figure 2
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> for EPD-deposited sample of GO at concentration 0.25 mg/mL, time of deposition 1 min.</p> Full article ">Figure 3
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> for EPD GO sample after the annealing treatment at 400 °C for 1 h.</p> Full article ">Figure 4
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> for drop-casted sample of GO at concentration 0.1 mg/mL in water.</p> Full article ">Figure 5
<p>Estimated <span class="html-italic">n</span> and <span class="html-italic">k</span> of GO in isopropanol films (0.1 mg/mL).</p> Full article ">
Open AccessArticle
Impact of Dispersive Solvent and Temperature on Supercapacitor Performance of N-Doped Reduced Graphene Oxide
by
Ankit Yadav, Rajeev Kumar, Deepu Joseph, Nygil Thomas, Fei Yan and Balaram Sahoo
C 2024, 10(4), 89; https://doi.org/10.3390/c10040089 - 10 Oct 2024
Abstract
This study evaluates the critical roles of the dispersion medium and temperature during the solvothermal synthesis of nitrogen-doped reduced graphene oxide (NG) for enhancing its performance as an active material in supercapacitor electrodes. Using a fixed volume of a solvent (THF, ethanol, acetonitrile,
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This study evaluates the critical roles of the dispersion medium and temperature during the solvothermal synthesis of nitrogen-doped reduced graphene oxide (NG) for enhancing its performance as an active material in supercapacitor electrodes. Using a fixed volume of a solvent (THF, ethanol, acetonitrile, water, N,N-Dimethylformamide, ethylene glycol, or N-Methyl-2-pyrrolidone) as the dispersive medium, a series of samples at different temperatures (60, 75, 95, 120, 150, 180, and 195 °C) are synthesized and investigated. A proper removal of the oxygen moieties from their surface and an optimum number of N-based defects are essential for a better reduction of graphene oxide and better stacking of the NG sheets. The origin of the supercapacitance of NG sheets can be correlated to the inherent properties such as the boiling point, viscosity, dipole moment, and dielectric constant of all the studied solvents, along with the synthesis temperature. Due to the achievement of a suitable synthesis environment, NG synthesized using N,N-Dimethylformamide at 150 °C displays an excellent supercapacitance value of 514 F/g at 0.5 A/g, which is the highest among all our samples and also competitive among several state-of-the-art lightweight carbon materials. Our work not only helps in understanding the origin of the supercapacitance exhibited by graphene-based materials but also tuning them through a suitable choice of synthesis conditions.
Full article
(This article belongs to the Special Issue Carbon and Related Composites for Sensors and Energy Storage: Synthesis, Properties, and Application)
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>SEM images of (<b>a</b>) NG-3-DMF-150 and (<b>b</b>) NG-3-H<sub>2</sub>O-150 samples.</p> Full article ">Figure 2
<p>The XRD pattern of the (<b>a</b>) GO and rGO, and (<b>b</b>–<b>h</b>) NG-3 samples synthesized in various dispersive media and at different temperatures, as indicated.</p> Full article ">Figure 3
<p>(<b>a</b>) Cyclic voltammograms of all the NG samples at different temperatures with various dispersive solvents, measured at a fixed scan rate of 5 mV/s. The solvents used for synthesis are (<b>a</b>) THF, (<b>b</b>) ethanol, (<b>c</b>) acetonitrile, (<b>d</b>) H<sub>2</sub>O, (<b>e</b>) DMF, (<b>f</b>) ethylene glycol, and (<b>g</b>) NMP.</p> Full article ">Figure 4
<p>(<b>a</b>) The galvanostatic charging–discharging (GCD) plots for all the NG samples synthesized at different temperatures with various dispersive solvents as indicated. (<b>a</b>) THF, (<b>b</b>) ethanol, (<b>c</b>) acetonitrile, (<b>d</b>) H<sub>2</sub>O, (<b>e</b>) DMF, (<b>f</b>) ethylene glycol, and (<b>g</b>) NMP. (<b>h</b>) The specific capacitance of all the NG samples is calculated from the discharging region of the GCD curves by using Equation (2).</p> Full article ">Figure 5
<p>EIS spectra of all our synthesized NG samples at different temperatures in various dispersive solvents.</p> Full article ">Figure 6
<p>XPS spectra of synthesized NG-3 sample (<b>left panel</b>) N 1s, (<b>middle panel</b>) C 1s, and (<b>right panel</b>) O 1s.</p> Full article ">Figure 7
<p>The wide XPS spectra of the synthesized samples in the full measured energy range.</p> Full article ">
Full article ">Figure 1
<p>SEM images of (<b>a</b>) NG-3-DMF-150 and (<b>b</b>) NG-3-H<sub>2</sub>O-150 samples.</p> Full article ">Figure 2
<p>The XRD pattern of the (<b>a</b>) GO and rGO, and (<b>b</b>–<b>h</b>) NG-3 samples synthesized in various dispersive media and at different temperatures, as indicated.</p> Full article ">Figure 3
<p>(<b>a</b>) Cyclic voltammograms of all the NG samples at different temperatures with various dispersive solvents, measured at a fixed scan rate of 5 mV/s. The solvents used for synthesis are (<b>a</b>) THF, (<b>b</b>) ethanol, (<b>c</b>) acetonitrile, (<b>d</b>) H<sub>2</sub>O, (<b>e</b>) DMF, (<b>f</b>) ethylene glycol, and (<b>g</b>) NMP.</p> Full article ">Figure 4
<p>(<b>a</b>) The galvanostatic charging–discharging (GCD) plots for all the NG samples synthesized at different temperatures with various dispersive solvents as indicated. (<b>a</b>) THF, (<b>b</b>) ethanol, (<b>c</b>) acetonitrile, (<b>d</b>) H<sub>2</sub>O, (<b>e</b>) DMF, (<b>f</b>) ethylene glycol, and (<b>g</b>) NMP. (<b>h</b>) The specific capacitance of all the NG samples is calculated from the discharging region of the GCD curves by using Equation (2).</p> Full article ">Figure 5
<p>EIS spectra of all our synthesized NG samples at different temperatures in various dispersive solvents.</p> Full article ">Figure 6
<p>XPS spectra of synthesized NG-3 sample (<b>left panel</b>) N 1s, (<b>middle panel</b>) C 1s, and (<b>right panel</b>) O 1s.</p> Full article ">Figure 7
<p>The wide XPS spectra of the synthesized samples in the full measured energy range.</p> Full article ">
Open AccessArticle
Role of Graphene Oxide in Disentangling Amyloid Beta Fibrils
by
Brianna Duswalt, Isabella Wolson and Isaac Macwan
C 2024, 10(4), 88; https://doi.org/10.3390/c10040088 - 3 Oct 2024
Abstract
Recently, the accumulation of Amyloid Beta (Aβ) in the brain has been linked to the development of Alzheimer’s disease (AD) through the formation of aggregated plaques and neurofibrillary tangles (NFTs). Although carbon nanoparticles were previously shown as having a potential to address AD,
[...] Read more.
Recently, the accumulation of Amyloid Beta (Aβ) in the brain has been linked to the development of Alzheimer’s disease (AD) through the formation of aggregated plaques and neurofibrillary tangles (NFTs). Although carbon nanoparticles were previously shown as having a potential to address AD, the interactions of Aβ with such nanoparticles have not been studied extensively. In this work, molecular dynamic simulations are utilized to simulate the interactions between a single atomic layer of graphene oxide (GO) and a 12-monomer Aβ fibril. These interactions are further compared to those between GO and five individual monomers of Aβ to further understand the conformational changes in Aβ as an individual monomer and as a component of the Aβ fibril. It was found that out of the 42 residues of the Aβ monomers, residues 27–42 are the most affected by the presence of GO. Furthermore, stability analysis through RMSD, conformational energies and salt bridges, along with nonbonding energy, illustrate that Aβ–Aβ interactions were successfully interrupted and dismantled by GO. Overall, the differences in the interactions between monomeric Aβ consisting of five monomers with GO, an Aβ fibril with GO, and control Aβ monomers among themselves, helped elucidate the potential that GO has to disentangle the Aβ tangles, both in case of individual monomers forming a cluster and as part of the Aβ fibril.
Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications)
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Figure 1
<p>Role of GO in disentangling the neurofibrillary tangles. (<b>A</b>) Progression from a single Aβ monomer as a protein tangle to the formation of neurofibrillary tangle clusters; (<b>B</b>) GO attracts the Aβ tangles and disintegrates the neurofibrillary tangles; and (<b>C</b>) adsorption of the 12-monomer Aβ fibril onto the surface of GO showing the adsorbed atoms of Aβ.</p> Full article ">Figure 2
<p>RMSD trajectories and COMs for individual Aβ monomers and 12-monomer Aβ fibril: (<b>A</b>) RMSD Trajectory of 12-Aβ-GO system; (<b>B</b>) average RMSD for the 5-Aβ system in the presence and absence of GO; (<b>C</b>) COM distance between GO and the Aβ fibril for the 12-Aβ-GO system; and (<b>D</b>) COM distance between the individual Aβ monomers in the presence and absence of GO for the 5-Aβ system.</p> Full article ">Figure 3
<p>Interaction energies for 12-monomer Aβ fibril and individual 5-Aβ monomers: (<b>A</b>) Van der Waals energy between the Aβ fibril and GO and electrostatic energy within the Aβ fibril in the presence of GO; (<b>B</b>) total conformational energy of the Aβ fibril in the presence of GO; (<b>C</b>) electrostatic energy with 5-Aβ in the presence and absence of GO, and the total Van der Waals energy between 5-Aβ and GO; and (<b>D</b>) total conformational energy of 5-Aβ monomers in the presence and absence of GO. Note: wGO—with GO.</p> Full article ">Figure 4
<p>Analysis of hydrogen bonds to quantify stability. (<b>A</b>) hydrogen bonds within the Aβ fibril in the presence of GO; (<b>B</b>) hydrogen bonds within the 5 Aβ monomers in the presence and absence of GO; (<b>C</b>) hydrogen bonds between the Aβ monomers forming clump 1 involving the segments AP1, 2AP1, and 3AP1 in the absence of GO; and (<b>D</b>) hydrogen bonds between the Aβ monomers forming clump 2 involving the segments 1AP1 and 4AP1 in the absence of GO. Note: wGO—With GO; noGO—without GO.</p> Full article ">Figure 5
<p>Optimal adsorption distance analysis based on the number of adsorbed atoms and interaction energy per adsorbed atom. (<b>A</b>) number of atoms with and without hydrogen as a function of the distance from the surface of GO for the Aβ fibril system; (<b>B</b>) number of atoms with and without hydrogen as a function of the distance from the surface of GO for the 5-Aβ system; (<b>C</b>) interaction energy of the adsorbed atoms as a function of the distance from the surface of GO for the Aβ fibril system; (<b>D</b>) interaction energy of the adsorbed atoms as a function of the distance from the surface of GO for the 5-Aβ system; (<b>E</b>) optimal adsorption distance as a function of the distance from the surface of GO for the Aβ fibril system; and (<b>F</b>) optimal adsorption distance as a function of the distance from the surface of GO for the 5-Aβ system.</p> Full article ">Figure 6
<p>Quantification of the number of interfacial water molecules and their hydrogen bonds. (<b>A</b>) interfacial water molecules within 5 Å of GO and Aβ fibril; (<b>B</b>) hydrogen bonds of the interfacial water molecules during the interactions between Aβ fibril and GO; (<b>C</b>) total interfacial water molecules within 5 Å of GO and the monomeric 5-Aβ system; and (<b>D</b>) total number of hydrogen bonds of the interfacial water molecules during the interactions between individual Aβ monomers and GO.</p> Full article ">
<p>Role of GO in disentangling the neurofibrillary tangles. (<b>A</b>) Progression from a single Aβ monomer as a protein tangle to the formation of neurofibrillary tangle clusters; (<b>B</b>) GO attracts the Aβ tangles and disintegrates the neurofibrillary tangles; and (<b>C</b>) adsorption of the 12-monomer Aβ fibril onto the surface of GO showing the adsorbed atoms of Aβ.</p> Full article ">Figure 2
<p>RMSD trajectories and COMs for individual Aβ monomers and 12-monomer Aβ fibril: (<b>A</b>) RMSD Trajectory of 12-Aβ-GO system; (<b>B</b>) average RMSD for the 5-Aβ system in the presence and absence of GO; (<b>C</b>) COM distance between GO and the Aβ fibril for the 12-Aβ-GO system; and (<b>D</b>) COM distance between the individual Aβ monomers in the presence and absence of GO for the 5-Aβ system.</p> Full article ">Figure 3
<p>Interaction energies for 12-monomer Aβ fibril and individual 5-Aβ monomers: (<b>A</b>) Van der Waals energy between the Aβ fibril and GO and electrostatic energy within the Aβ fibril in the presence of GO; (<b>B</b>) total conformational energy of the Aβ fibril in the presence of GO; (<b>C</b>) electrostatic energy with 5-Aβ in the presence and absence of GO, and the total Van der Waals energy between 5-Aβ and GO; and (<b>D</b>) total conformational energy of 5-Aβ monomers in the presence and absence of GO. Note: wGO—with GO.</p> Full article ">Figure 4
<p>Analysis of hydrogen bonds to quantify stability. (<b>A</b>) hydrogen bonds within the Aβ fibril in the presence of GO; (<b>B</b>) hydrogen bonds within the 5 Aβ monomers in the presence and absence of GO; (<b>C</b>) hydrogen bonds between the Aβ monomers forming clump 1 involving the segments AP1, 2AP1, and 3AP1 in the absence of GO; and (<b>D</b>) hydrogen bonds between the Aβ monomers forming clump 2 involving the segments 1AP1 and 4AP1 in the absence of GO. Note: wGO—With GO; noGO—without GO.</p> Full article ">Figure 5
<p>Optimal adsorption distance analysis based on the number of adsorbed atoms and interaction energy per adsorbed atom. (<b>A</b>) number of atoms with and without hydrogen as a function of the distance from the surface of GO for the Aβ fibril system; (<b>B</b>) number of atoms with and without hydrogen as a function of the distance from the surface of GO for the 5-Aβ system; (<b>C</b>) interaction energy of the adsorbed atoms as a function of the distance from the surface of GO for the Aβ fibril system; (<b>D</b>) interaction energy of the adsorbed atoms as a function of the distance from the surface of GO for the 5-Aβ system; (<b>E</b>) optimal adsorption distance as a function of the distance from the surface of GO for the Aβ fibril system; and (<b>F</b>) optimal adsorption distance as a function of the distance from the surface of GO for the 5-Aβ system.</p> Full article ">Figure 6
<p>Quantification of the number of interfacial water molecules and their hydrogen bonds. (<b>A</b>) interfacial water molecules within 5 Å of GO and Aβ fibril; (<b>B</b>) hydrogen bonds of the interfacial water molecules during the interactions between Aβ fibril and GO; (<b>C</b>) total interfacial water molecules within 5 Å of GO and the monomeric 5-Aβ system; and (<b>D</b>) total number of hydrogen bonds of the interfacial water molecules during the interactions between individual Aβ monomers and GO.</p> Full article ">
Open AccessArticle
Self-Assembled Synthesis of Graphene Tubes from Melamine Catalyzed by Calcium Carbonate
by
Wenping Zeng, Jingxiang Meng, Xinbo Zheng, Tingting Mao, Jintao Huang and Yonggang Min
C 2024, 10(4), 87; https://doi.org/10.3390/c10040087 - 26 Sep 2024
Abstract
This study investigates the carbon products generated by melamine under various heat-treatment temperatures with the catalysis of calcium carbonate. We discovered that the cost-effective precursor melamine readily self-assembles and curls into graphene tubes when catalyzed by the alkaline earth salt CaCO3 at
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This study investigates the carbon products generated by melamine under various heat-treatment temperatures with the catalysis of calcium carbonate. We discovered that the cost-effective precursor melamine readily self-assembles and curls into graphene tubes when catalyzed by the alkaline earth salt CaCO3 at elevated temperatures. Under heat-treatment conditions of 1100 °C and 1200 °C, the growth morphology of graphene tubes with open structures and exceptionally large diameters was observed, and the diameters reached the micron level. These products exhibit a high degree of carbonization and an extremely low nitrogen content, as low as 1.7%. Further, the intensity ratio (ID/IG) of the D band and the G band is as low as 0.79 in Raman characterization. The results show that the products have a certain graphite structure, which proves the catalytic activity of CaCO3. This is attributed to the incorporation of CaCO3 into the raw material system, which impedes the complete thermal decomposition of melamine. On the other hand, the resulting CaO particles are evenly distributed along the tubular products, providing certain support for their self-assembly and growth, thereby achieving the efficient growth of graphene tubes.
Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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Figure 1
<p>SEM images of (<b>a</b>) the raw material system and the carbon products obtained with different heat-treatment temperatures: (<b>b</b>) 1000 °C, (<b>c</b>) 1100 °C, and (<b>d</b>) 1200 °C.</p> Full article ">Figure 2
<p>SEM images of various GTs and corresponding C, N, O, and Ca element mapping spectra with different heat-treatment temperatures: (<b>a</b>) 1100 °C and (<b>b</b>) 1200 °C.</p> Full article ">Figure 3
<p>(<b>a</b>) TGA curves and corresponding TGA characteristic thermal data of the CaCO<sub>3</sub>/melamine and melamine samples. (<b>b</b>) Raman spectra of the powder product obtained at 900–1200 °C. (<b>c</b>) FT-IR spectra of the powder product obtained at 800–1200 °C.</p> Full article ">Figure 4
<p>(<b>a</b>) C1s high-resolution XPS spectra and (<b>b</b>) N1s high-resolution XPS spectra of the carbon products obtained at 800 °C and 1200 °C.</p> Full article ">Figure 5
<p>(<b>a</b>) XRD patterns of the powder product obtained at 800–1200 °C. (<b>b</b>) The corresponding 2θ is a locally amplified diffraction pattern in the range of 25–28°.</p> Full article ">
<p>SEM images of (<b>a</b>) the raw material system and the carbon products obtained with different heat-treatment temperatures: (<b>b</b>) 1000 °C, (<b>c</b>) 1100 °C, and (<b>d</b>) 1200 °C.</p> Full article ">Figure 2
<p>SEM images of various GTs and corresponding C, N, O, and Ca element mapping spectra with different heat-treatment temperatures: (<b>a</b>) 1100 °C and (<b>b</b>) 1200 °C.</p> Full article ">Figure 3
<p>(<b>a</b>) TGA curves and corresponding TGA characteristic thermal data of the CaCO<sub>3</sub>/melamine and melamine samples. (<b>b</b>) Raman spectra of the powder product obtained at 900–1200 °C. (<b>c</b>) FT-IR spectra of the powder product obtained at 800–1200 °C.</p> Full article ">Figure 4
<p>(<b>a</b>) C1s high-resolution XPS spectra and (<b>b</b>) N1s high-resolution XPS spectra of the carbon products obtained at 800 °C and 1200 °C.</p> Full article ">Figure 5
<p>(<b>a</b>) XRD patterns of the powder product obtained at 800–1200 °C. (<b>b</b>) The corresponding 2θ is a locally amplified diffraction pattern in the range of 25–28°.</p> Full article ">
Open AccessReview
Recent Advances in Carbon-Based Interfacial Photothermal Converters for Seawater Desalination: A Review
by
Xiaoyu Jia, Yuke Niu, Shufang Zhu, Hongwei He and Xu Yan
C 2024, 10(3), 86; https://doi.org/10.3390/c10030086 - 22 Sep 2024
Abstract
Along with the rapid development of society, freshwater shortages have become a global concern. Although existing desalination technologies have alleviated this pressure to some extent, their long-term environmental impact and energy consumption are still questionable. Therefore, it is necessary to find a new
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Along with the rapid development of society, freshwater shortages have become a global concern. Although existing desalination technologies have alleviated this pressure to some extent, their long-term environmental impact and energy consumption are still questionable. Therefore, it is necessary to find a new effective way for seawater desalination with cleaner energy. Solar-driven interfacial water evaporation technology has the advantages of environmental protection, energy saving, high evaporation efficiency, low cost, and strong sustainability, and is considered one of the most effective technologies to relieve water resource stress. This review summarized the recent advances in carbon-based interfacial photothermal converters focused on the preparation methods of 2D and 3D photothermal absorbers, the potential ways to enhance the efficiency of photothermal conversion. Finally, this paper proposed the challenges and future trends of interfacial photothermal converters.
Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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Figure 1
<p>Solar-driven evaporation through various forms of solar heating. (<b>a</b>) Bottom-heating-based evaporation. (<b>b</b>) Bulk-heating-based evaporation. (<b>c</b>) Interfacial heating-based evaporation [<a href="#B4-carbon-10-00086" class="html-bibr">4</a>]. © 2018 Springer Nature Limited.</p> Full article ">Figure 2
<p>Different mechanisms of the photothermal effect with the corresponding light absorption range [<a href="#B13-carbon-10-00086" class="html-bibr">13</a>]. (<b>a</b>) Metal-based materials. (<b>b</b>) Semiconductor materials. (<b>c</b>) Organic polymer materials. © The Royal Society of Chemistry 2019.</p> Full article ">Figure 3
<p>(<b>a</b>) Schematic diagram of photothermal converter prepared by electrospinning [<a href="#B35-carbon-10-00086" class="html-bibr">35</a>]. © The Royal Society of Chemistry 2018. (<b>b</b>) Schematic and structure of a three-layer unidirectional water-transporting electrostatic spunlace membrane [<a href="#B36-carbon-10-00086" class="html-bibr">36</a>]. © 2023 Elsevier Inc.</p> Full article ">Figure 4
<p>(<b>a</b>) Schematic diagram of preparation of multilayer polypyridine nanosheets by surface deposition [<a href="#B43-carbon-10-00086" class="html-bibr">43</a>]. © 2019 WILEY. (<b>b</b>) Preparation procedure for the SiO<sub>2</sub>/MXene/HPTFE Janus membrane [<a href="#B45-carbon-10-00086" class="html-bibr">45</a>]. © 2021 American Chemical Society.</p> Full article ">Figure 5
<p>(<b>a</b>) Schematic illustrating the preparation of the basalt-fiber PTM [<a href="#B46-carbon-10-00086" class="html-bibr">46</a>]. © 2020 Elsevier B.V. (<b>b</b>) Schematic diagram of the preparation of the willow catkins composite membrane [<a href="#B47-carbon-10-00086" class="html-bibr">47</a>]. © 2020 American Chemical Society.</p> Full article ">Figure 6
<p>(<b>a</b>) Fabrication and interfacial evaporation process of the in situ sulfurization of hierarchical PAN@CuS fabric [<a href="#B48-carbon-10-00086" class="html-bibr">48</a>]. © 2021 American Chemical Society. (<b>b</b>) A schematic diagram of light trapping mechanism and salt resistance of seawater desalination of the TLL light-trapping structure [<a href="#B49-carbon-10-00086" class="html-bibr">49</a>]. © 2022 Elsevier Ltd.</p> Full article ">Figure 7
<p>(<b>a</b>) F-wood for solar steam generation by carbonization method [<a href="#B37-carbon-10-00086" class="html-bibr">37</a>]. Copyright © 2017 American Chemical Society. (<b>b</b>) Preparation of different carbonized wood solar evaporators by surface carbonization [<a href="#B56-carbon-10-00086" class="html-bibr">56</a>]. © 2022 Elsevier Ltd.</p> Full article ">Figure 8
<p>Schematic diagram of solar evaporator prepared by various surface modification methods. (<b>a</b>) Depositing dopamine and silver nanowires onto natural wood [<a href="#B57-carbon-10-00086" class="html-bibr">57</a>]. © 2020 American Chemical Society. (<b>b</b>) Brushing with aluminum phosphate and heated coated wood surfaces [<a href="#B58-carbon-10-00086" class="html-bibr">58</a>]. © 2020 American Chemical Society. (<b>c</b>) Spraying graphene [<a href="#B59-carbon-10-00086" class="html-bibr">59</a>]. © 2018 WILEY. (<b>d</b>) Coating melamine foam by simple impregnation and in situ polymerization [<a href="#B60-carbon-10-00086" class="html-bibr">60</a>]. © 2023 Elsevier Inc.</p> Full article ">Figure 9
<p>(<b>a</b>) AgNPs and reduced graphene oxide composite aerogels were synthesized by hydrothermal reduction and freeze-drying [<a href="#B27-carbon-10-00086" class="html-bibr">27</a>]. © 2022 Elsevier B.V. (<b>b</b>) PC@PDA-C aerogel with 3D interconnected structures inspired by nature luffa for solar vapor generation [<a href="#B64-carbon-10-00086" class="html-bibr">64</a>] © 2021 Elsevier B.V. (<b>c</b>) The schematic fabrication process of SMC-based solar-driven interfacial evaporator [<a href="#B65-carbon-10-00086" class="html-bibr">65</a>]. © 2023 Elsevier B.V.</p> Full article ">Figure 10
<p>(<b>a</b>) Schematic illustration for the fabrication process of bilayer CB@NF/PVA/starch composites [<a href="#B74-carbon-10-00086" class="html-bibr">74</a>]. © 2022 Elsevier Ltd. (<b>b</b>) Solar steam power generation schematic diagram of hydrogel based on salt-tolerant anionic polyelectrolyte [<a href="#B75-carbon-10-00086" class="html-bibr">75</a>]. © 2021 Elsevier B.V.</p> Full article ">Figure 11
<p>Schematic illustration of the 3D printing process and the structure of the photothermal converter [<a href="#B77-carbon-10-00086" class="html-bibr">77</a>]. (<b>a</b>) Schematic diagram showing the fabrication process of 3D printing. (<b>b</b>) Schematic diagram of the structure of the 3D-printed photothermal converter, including the CNT/GO layer, the GO/CNT layer, and the GO/NFC wall. (<b>c</b>) Photograph showing the light weight of the photothermal converter. © 2017 WILEY.</p> Full article ">Figure 12
<p>Schematic diagram of methods to improve the performance of photothermal conversion [<a href="#B47-carbon-10-00086" class="html-bibr">47</a>,<a href="#B79-carbon-10-00086" class="html-bibr">79</a>,<a href="#B80-carbon-10-00086" class="html-bibr">80</a>,<a href="#B81-carbon-10-00086" class="html-bibr">81</a>]. © 2020 American Chemical Society. © 2018 Elsevier Ltd.. © 2019 International Solar Energy Society.</p> Full article ">Figure 13
<p>(<b>a</b>) (TiO<sub>2–x</sub> H<sub>x</sub>), the high-pressure hydrogenated black titania (HP-TiO<sub>2</sub>) and pristine TiO<sub>2</sub> [<a href="#B82-carbon-10-00086" class="html-bibr">82</a>]. © 2013 WILEY. (<b>b</b>) UV-VIS-NIR spectra of CNTs, CNTs-PAMAM, and CNTs-PAMAM-Ag<sub>2</sub>S [<a href="#B83-carbon-10-00086" class="html-bibr">83</a>]. © 2019 Elsevier B.V. (<b>c</b>) The absorption spectrum of nylon/carbon cloth of different concentrations in the dry and wet state. Illustration: the dry composite photothermal film is shown on the left, and the wet composite photothermal film is shown on the right [<a href="#B35-carbon-10-00086" class="html-bibr">35</a>]. © The Royal Society of Chemistry 2018.</p> Full article ">Figure 14
<p>(<b>a</b>) Schematic illustration of light trapping by surface structures formed on multilayer PPy nanosheets [<a href="#B43-carbon-10-00086" class="html-bibr">43</a>]. (<b>b</b>) Diffuse reflectance spectra of the air-laid paper substrate coated with different layers of PPy nanosheets [<a href="#B43-carbon-10-00086" class="html-bibr">43</a>]. © 2019 WILEY. (<b>c</b>) Schematic diagram of the interaction between the 2D planar membrane, folded 3D membrane surfaces, and incident light [<a href="#B84-carbon-10-00086" class="html-bibr">84</a>]. (<b>d</b>) Schematic diagram of 3D evaporator prepared by the folding process [<a href="#B84-carbon-10-00086" class="html-bibr">84</a>]. © 2023 Elsevier Ltd.</p> Full article ">Figure 15
<p>(<b>a</b>) Schematic illustration of the evaporation process of nitrogen-doped three-dimensional porous graphene sheets. (<b>b</b>) Thermal conductivity of nitrogen-doped and undoped porous graphene samples grown at different temperatures [<a href="#B97-carbon-10-00086" class="html-bibr">97</a>]. © 2015 WILEY. (<b>c</b>) Photograph and cross-sectional schematic of the bilayer structure. (<b>d</b>–<b>g</b>) Thermal conductivity measurement of each layer in the bilayer structure using an infrared imaging system: (<b>d</b>) detached graphene in air; (<b>e</b>) carbon foam in air; (<b>f</b>) detached graphene with water; (<b>g</b>) carbon foam filled with water. The insets in the figures are infrared thermal images captured by an infrared camera [<a href="#B98-carbon-10-00086" class="html-bibr">98</a>]. © 2014, Springer Nature Limited.</p> Full article ">Figure 16
<p>(<b>a</b>) Schematic diagram and physical images of the F-F-wood structure. In the second image, the wood is shown serving as a water pathway, while in the third image, polyphenylene foam is filled inside the wood to act as an insulating layer. The fourth image illustrates the carbonized surface serving as the light absorber [<a href="#B99-carbon-10-00086" class="html-bibr">99</a>]. © 2021, Elsevier. (<b>b</b>) Conceptual diagram of a mushroom-based solar evaporation device under sunlight conditions [<a href="#B53-carbon-10-00086" class="html-bibr">53</a>]. © 2017 WILEY.</p> Full article ">Figure 17
<p>(<b>a</b>) CNF-CNT aerogel 3D water channel [<a href="#B100-carbon-10-00086" class="html-bibr">100</a>]. © 2018, American Chemical Society. (<b>b</b>) Two-dimensional cellulose paper water channel [<a href="#B39-carbon-10-00086" class="html-bibr">39</a>]. © 2016 National Academy of Sciences. (<b>c</b>) One-dimensional hydrophilic cotton yarn water channel [<a href="#B101-carbon-10-00086" class="html-bibr">101</a>]. © 2020 Elsevier B.V. (<b>d</b>) Evaporator structure [<a href="#B84-carbon-10-00086" class="html-bibr">84</a>]. © 2023 Elsevier Ltd.</p> Full article ">Figure 18
<p>(<b>a</b>) Illustration of an evaporative system demonstrating the removal of salt through one-way saltwater flow [<a href="#B104-carbon-10-00086" class="html-bibr">104</a>]. © 2020 American Chemical Society. (<b>b</b>) Schematic diagram of the Janus PMX membrane structure [<a href="#B105-carbon-10-00086" class="html-bibr">105</a>]. (<b>c</b>) Comparison of salt deposition on pure MXene membrane and Janus PMX membrane [<a href="#B105-carbon-10-00086" class="html-bibr">105</a>]. Copyright © 2021 American Chemical Society. (<b>d</b>) Illustration of a vaporizer depicting the process of evaporation and the principle of salt crystal formation. It also includes a photograph of the vaporizer [<a href="#B106-carbon-10-00086" class="html-bibr">106</a>]. Copyright © 2021, the author(s).</p> Full article ">
<p>Solar-driven evaporation through various forms of solar heating. (<b>a</b>) Bottom-heating-based evaporation. (<b>b</b>) Bulk-heating-based evaporation. (<b>c</b>) Interfacial heating-based evaporation [<a href="#B4-carbon-10-00086" class="html-bibr">4</a>]. © 2018 Springer Nature Limited.</p> Full article ">Figure 2
<p>Different mechanisms of the photothermal effect with the corresponding light absorption range [<a href="#B13-carbon-10-00086" class="html-bibr">13</a>]. (<b>a</b>) Metal-based materials. (<b>b</b>) Semiconductor materials. (<b>c</b>) Organic polymer materials. © The Royal Society of Chemistry 2019.</p> Full article ">Figure 3
<p>(<b>a</b>) Schematic diagram of photothermal converter prepared by electrospinning [<a href="#B35-carbon-10-00086" class="html-bibr">35</a>]. © The Royal Society of Chemistry 2018. (<b>b</b>) Schematic and structure of a three-layer unidirectional water-transporting electrostatic spunlace membrane [<a href="#B36-carbon-10-00086" class="html-bibr">36</a>]. © 2023 Elsevier Inc.</p> Full article ">Figure 4
<p>(<b>a</b>) Schematic diagram of preparation of multilayer polypyridine nanosheets by surface deposition [<a href="#B43-carbon-10-00086" class="html-bibr">43</a>]. © 2019 WILEY. (<b>b</b>) Preparation procedure for the SiO<sub>2</sub>/MXene/HPTFE Janus membrane [<a href="#B45-carbon-10-00086" class="html-bibr">45</a>]. © 2021 American Chemical Society.</p> Full article ">Figure 5
<p>(<b>a</b>) Schematic illustrating the preparation of the basalt-fiber PTM [<a href="#B46-carbon-10-00086" class="html-bibr">46</a>]. © 2020 Elsevier B.V. (<b>b</b>) Schematic diagram of the preparation of the willow catkins composite membrane [<a href="#B47-carbon-10-00086" class="html-bibr">47</a>]. © 2020 American Chemical Society.</p> Full article ">Figure 6
<p>(<b>a</b>) Fabrication and interfacial evaporation process of the in situ sulfurization of hierarchical PAN@CuS fabric [<a href="#B48-carbon-10-00086" class="html-bibr">48</a>]. © 2021 American Chemical Society. (<b>b</b>) A schematic diagram of light trapping mechanism and salt resistance of seawater desalination of the TLL light-trapping structure [<a href="#B49-carbon-10-00086" class="html-bibr">49</a>]. © 2022 Elsevier Ltd.</p> Full article ">Figure 7
<p>(<b>a</b>) F-wood for solar steam generation by carbonization method [<a href="#B37-carbon-10-00086" class="html-bibr">37</a>]. Copyright © 2017 American Chemical Society. (<b>b</b>) Preparation of different carbonized wood solar evaporators by surface carbonization [<a href="#B56-carbon-10-00086" class="html-bibr">56</a>]. © 2022 Elsevier Ltd.</p> Full article ">Figure 8
<p>Schematic diagram of solar evaporator prepared by various surface modification methods. (<b>a</b>) Depositing dopamine and silver nanowires onto natural wood [<a href="#B57-carbon-10-00086" class="html-bibr">57</a>]. © 2020 American Chemical Society. (<b>b</b>) Brushing with aluminum phosphate and heated coated wood surfaces [<a href="#B58-carbon-10-00086" class="html-bibr">58</a>]. © 2020 American Chemical Society. (<b>c</b>) Spraying graphene [<a href="#B59-carbon-10-00086" class="html-bibr">59</a>]. © 2018 WILEY. (<b>d</b>) Coating melamine foam by simple impregnation and in situ polymerization [<a href="#B60-carbon-10-00086" class="html-bibr">60</a>]. © 2023 Elsevier Inc.</p> Full article ">Figure 9
<p>(<b>a</b>) AgNPs and reduced graphene oxide composite aerogels were synthesized by hydrothermal reduction and freeze-drying [<a href="#B27-carbon-10-00086" class="html-bibr">27</a>]. © 2022 Elsevier B.V. (<b>b</b>) PC@PDA-C aerogel with 3D interconnected structures inspired by nature luffa for solar vapor generation [<a href="#B64-carbon-10-00086" class="html-bibr">64</a>] © 2021 Elsevier B.V. (<b>c</b>) The schematic fabrication process of SMC-based solar-driven interfacial evaporator [<a href="#B65-carbon-10-00086" class="html-bibr">65</a>]. © 2023 Elsevier B.V.</p> Full article ">Figure 10
<p>(<b>a</b>) Schematic illustration for the fabrication process of bilayer CB@NF/PVA/starch composites [<a href="#B74-carbon-10-00086" class="html-bibr">74</a>]. © 2022 Elsevier Ltd. (<b>b</b>) Solar steam power generation schematic diagram of hydrogel based on salt-tolerant anionic polyelectrolyte [<a href="#B75-carbon-10-00086" class="html-bibr">75</a>]. © 2021 Elsevier B.V.</p> Full article ">Figure 11
<p>Schematic illustration of the 3D printing process and the structure of the photothermal converter [<a href="#B77-carbon-10-00086" class="html-bibr">77</a>]. (<b>a</b>) Schematic diagram showing the fabrication process of 3D printing. (<b>b</b>) Schematic diagram of the structure of the 3D-printed photothermal converter, including the CNT/GO layer, the GO/CNT layer, and the GO/NFC wall. (<b>c</b>) Photograph showing the light weight of the photothermal converter. © 2017 WILEY.</p> Full article ">Figure 12
<p>Schematic diagram of methods to improve the performance of photothermal conversion [<a href="#B47-carbon-10-00086" class="html-bibr">47</a>,<a href="#B79-carbon-10-00086" class="html-bibr">79</a>,<a href="#B80-carbon-10-00086" class="html-bibr">80</a>,<a href="#B81-carbon-10-00086" class="html-bibr">81</a>]. © 2020 American Chemical Society. © 2018 Elsevier Ltd.. © 2019 International Solar Energy Society.</p> Full article ">Figure 13
<p>(<b>a</b>) (TiO<sub>2–x</sub> H<sub>x</sub>), the high-pressure hydrogenated black titania (HP-TiO<sub>2</sub>) and pristine TiO<sub>2</sub> [<a href="#B82-carbon-10-00086" class="html-bibr">82</a>]. © 2013 WILEY. (<b>b</b>) UV-VIS-NIR spectra of CNTs, CNTs-PAMAM, and CNTs-PAMAM-Ag<sub>2</sub>S [<a href="#B83-carbon-10-00086" class="html-bibr">83</a>]. © 2019 Elsevier B.V. (<b>c</b>) The absorption spectrum of nylon/carbon cloth of different concentrations in the dry and wet state. Illustration: the dry composite photothermal film is shown on the left, and the wet composite photothermal film is shown on the right [<a href="#B35-carbon-10-00086" class="html-bibr">35</a>]. © The Royal Society of Chemistry 2018.</p> Full article ">Figure 14
<p>(<b>a</b>) Schematic illustration of light trapping by surface structures formed on multilayer PPy nanosheets [<a href="#B43-carbon-10-00086" class="html-bibr">43</a>]. (<b>b</b>) Diffuse reflectance spectra of the air-laid paper substrate coated with different layers of PPy nanosheets [<a href="#B43-carbon-10-00086" class="html-bibr">43</a>]. © 2019 WILEY. (<b>c</b>) Schematic diagram of the interaction between the 2D planar membrane, folded 3D membrane surfaces, and incident light [<a href="#B84-carbon-10-00086" class="html-bibr">84</a>]. (<b>d</b>) Schematic diagram of 3D evaporator prepared by the folding process [<a href="#B84-carbon-10-00086" class="html-bibr">84</a>]. © 2023 Elsevier Ltd.</p> Full article ">Figure 15
<p>(<b>a</b>) Schematic illustration of the evaporation process of nitrogen-doped three-dimensional porous graphene sheets. (<b>b</b>) Thermal conductivity of nitrogen-doped and undoped porous graphene samples grown at different temperatures [<a href="#B97-carbon-10-00086" class="html-bibr">97</a>]. © 2015 WILEY. (<b>c</b>) Photograph and cross-sectional schematic of the bilayer structure. (<b>d</b>–<b>g</b>) Thermal conductivity measurement of each layer in the bilayer structure using an infrared imaging system: (<b>d</b>) detached graphene in air; (<b>e</b>) carbon foam in air; (<b>f</b>) detached graphene with water; (<b>g</b>) carbon foam filled with water. The insets in the figures are infrared thermal images captured by an infrared camera [<a href="#B98-carbon-10-00086" class="html-bibr">98</a>]. © 2014, Springer Nature Limited.</p> Full article ">Figure 16
<p>(<b>a</b>) Schematic diagram and physical images of the F-F-wood structure. In the second image, the wood is shown serving as a water pathway, while in the third image, polyphenylene foam is filled inside the wood to act as an insulating layer. The fourth image illustrates the carbonized surface serving as the light absorber [<a href="#B99-carbon-10-00086" class="html-bibr">99</a>]. © 2021, Elsevier. (<b>b</b>) Conceptual diagram of a mushroom-based solar evaporation device under sunlight conditions [<a href="#B53-carbon-10-00086" class="html-bibr">53</a>]. © 2017 WILEY.</p> Full article ">Figure 17
<p>(<b>a</b>) CNF-CNT aerogel 3D water channel [<a href="#B100-carbon-10-00086" class="html-bibr">100</a>]. © 2018, American Chemical Society. (<b>b</b>) Two-dimensional cellulose paper water channel [<a href="#B39-carbon-10-00086" class="html-bibr">39</a>]. © 2016 National Academy of Sciences. (<b>c</b>) One-dimensional hydrophilic cotton yarn water channel [<a href="#B101-carbon-10-00086" class="html-bibr">101</a>]. © 2020 Elsevier B.V. (<b>d</b>) Evaporator structure [<a href="#B84-carbon-10-00086" class="html-bibr">84</a>]. © 2023 Elsevier Ltd.</p> Full article ">Figure 18
<p>(<b>a</b>) Illustration of an evaporative system demonstrating the removal of salt through one-way saltwater flow [<a href="#B104-carbon-10-00086" class="html-bibr">104</a>]. © 2020 American Chemical Society. (<b>b</b>) Schematic diagram of the Janus PMX membrane structure [<a href="#B105-carbon-10-00086" class="html-bibr">105</a>]. (<b>c</b>) Comparison of salt deposition on pure MXene membrane and Janus PMX membrane [<a href="#B105-carbon-10-00086" class="html-bibr">105</a>]. Copyright © 2021 American Chemical Society. (<b>d</b>) Illustration of a vaporizer depicting the process of evaporation and the principle of salt crystal formation. It also includes a photograph of the vaporizer [<a href="#B106-carbon-10-00086" class="html-bibr">106</a>]. Copyright © 2021, the author(s).</p> Full article ">
Open AccessArticle
Numerical Assessment of Effective Elastic Properties of Needled Carbon/Carbon Composites Based on a Multiscale Method
by
Jian Ge, Xujiang Chao, Haoteng Hu, Wenlong Tian, Weiqi Li and Lehua Qi
C 2024, 10(3), 85; https://doi.org/10.3390/c10030085 - 16 Sep 2024
Abstract
Needled carbon/carbon composites contain complex microstructures such as irregular pores, anisotropic pyrolytic carbon, and interphases between fibers and pyrolytic carbon matrices. Additionally, these composites have hierarchical structures including weftless plies, short-cut fiber plies, and needled regions. To predict the effective elastic properties of
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Needled carbon/carbon composites contain complex microstructures such as irregular pores, anisotropic pyrolytic carbon, and interphases between fibers and pyrolytic carbon matrices. Additionally, these composites have hierarchical structures including weftless plies, short-cut fiber plies, and needled regions. To predict the effective elastic properties of needled carbon/carbon composites, this paper proposes a novel sequential multiscale method. At the microscale, representative volume element (RVE) models are established based on the microstructures of the weftless ply, short-cut fiber ply, and needled region, respectively. In the microscale RVE model, a modified Voronoi tessellation method is developed to characterize anisotropic pyrolytic carbon matrices. At the macroscale, an RVE model containing hierarchical structures is developed to predict the effective elastic properties of needled carbon/carbon composites. For the data interaction between scales, the homogenization results of microscale models are used as inputs for the macroscale model. By comparing these against the experimental results, the proposed multiscale model is validated. Furthermore, the effect of porosity on the effective elastic properties of needled carbon/carbon composites is investigated based on the multiscale model. The results show that the effective elastic properties of needled carbon/carbon composites decrease with the increase in porosity, but the extent of decrease is different in different directions.
Full article
(This article belongs to the Special Issue Micro/Nanofabrication of Carbon-Based Devices and Their Applications)
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>The microstructural illustration of needled carbon/carbon composites.</p> Full article ">Figure 2
<p>(<b>a</b>) The SEM image of the weftless ply and (<b>b</b>) the distribution of the fiber diameter.</p> Full article ">Figure 3
<p>Illustration of the ICVI process, where the precursor gas enters the reaction chamber and reacts on the surface of carbon fibers to obtain pyrolytic carbon, and the temperature uniformity is assured by the graphite heater.</p> Full article ">Figure 4
<p>(<b>a</b>) Microstructures of needled carbon/carbon composites, where <span class="html-italic">t<sub>s</sub></span> is the thickness of the short-cut fiber ply, <span class="html-italic">t<sub>u</sub></span> is the thickness of the weftless ply, and <span class="html-italic">D<sub>F</sub></span> is the diameter of the needled region. (<b>b</b>) Short-cut fiber ply lies between the 0° and 90° weftless plies. (<b>c</b>) The pyrolytic carbon morphology under the polarized light microscope. (<b>d</b>–<b>f</b>) The grayscale histograms of (<b>a</b>–<b>c</b>) are presented, respectively.</p> Full article ">Figure 5
<p>The schematic diagram of the tensile test of needled C/C composites.</p> Full article ">Figure 6
<p>The multiscale scheme for predicting the effective elastic properties of needled C/C composites.</p> Full article ">Figure 7
<p>(<b>a</b>) The RVE model of the weftless ply before partitioning the equivalent matrix, and (<b>b</b>) the RVE model after partitioning the equivalent matrix.</p> Full article ">Figure 8
<p>(<b>a</b>) The RVE model of the short-cut fiber ply before partitioning the equivalent matrix, and (<b>b</b>) the RVE model after partitioning the equivalent matrix.</p> Full article ">Figure 9
<p>Illustration of the RVE model of the needled fiber region.</p> Full article ">Figure 10
<p>The macroscale model of needled C/C composites.</p> Full article ">Figure 11
<p>Effects of the mesh size on (<b>a</b>) <span class="html-italic">E</span><sub>11</sub>/<span class="html-italic">E</span><sub>22</sub> and <span class="html-italic">E</span><sub>33</sub>, (<b>b</b>) <span class="html-italic">G</span><sub>12</sub> and <span class="html-italic">G</span><sub>13</sub>/<span class="html-italic">G</span><sub>23</sub>, (<b>c</b>) <span class="html-italic">ν</span><sub>12</sub> and <span class="html-italic">ν</span><sub>13</sub>/<span class="html-italic">ν</span><sub>23</sub>, and (<b>d</b>) the relative error.</p> Full article ">Figure 12
<p>Effects of the model length on (<b>a</b>) <span class="html-italic">E</span><sub>11</sub>/<span class="html-italic">E</span><sub>22</sub> and <span class="html-italic">E</span><sub>33</sub>, (<b>b</b>) <span class="html-italic">G</span><sub>12</sub> and <span class="html-italic">G</span><sub>13</sub>/<span class="html-italic">G</span><sub>23</sub>, (<b>c</b>) <span class="html-italic">ν</span><sub>12</sub> and <span class="html-italic">ν</span><sub>13</sub>/<span class="html-italic">ν</span><sub>23</sub>, and (d) the relative error.</p> Full article ">Figure 13
<p>Effects of the model thickness on (<b>a</b>) <span class="html-italic">E</span><sub>11</sub>/<span class="html-italic">E</span><sub>22</sub> and <span class="html-italic">E</span><sub>33</sub>, (<b>b</b>) <span class="html-italic">G</span><sub>12</sub> and <span class="html-italic">G</span><sub>13</sub>/<span class="html-italic">G</span><sub>23</sub>, (<b>c</b>) <span class="html-italic">ν</span><sub>12</sub> and <span class="html-italic">ν</span><sub>13</sub>/<span class="html-italic">ν</span><sub>23</sub>, and (<b>d</b>) the relative error.</p> Full article ">Figure 14
<p>Effects of porosity <span class="html-italic">V<sub>p</sub></span> on the effective elastic properties of (<b>a1</b>,<b>a2</b>) the needled region, (<b>b1</b>,<b>b2</b>) weftless ply, (<b>c1</b>,<b>c2</b>) short-cut fiber ply, and (<b>d1</b>,<b>d2</b>) needled C/C composite.</p> Full article ">Figure 14 Cont.
<p>Effects of porosity <span class="html-italic">V<sub>p</sub></span> on the effective elastic properties of (<b>a1</b>,<b>a2</b>) the needled region, (<b>b1</b>,<b>b2</b>) weftless ply, (<b>c1</b>,<b>c2</b>) short-cut fiber ply, and (<b>d1</b>,<b>d2</b>) needled C/C composite.</p> Full article ">
Full article ">Figure 1
<p>The microstructural illustration of needled carbon/carbon composites.</p> Full article ">Figure 2
<p>(<b>a</b>) The SEM image of the weftless ply and (<b>b</b>) the distribution of the fiber diameter.</p> Full article ">Figure 3
<p>Illustration of the ICVI process, where the precursor gas enters the reaction chamber and reacts on the surface of carbon fibers to obtain pyrolytic carbon, and the temperature uniformity is assured by the graphite heater.</p> Full article ">Figure 4
<p>(<b>a</b>) Microstructures of needled carbon/carbon composites, where <span class="html-italic">t<sub>s</sub></span> is the thickness of the short-cut fiber ply, <span class="html-italic">t<sub>u</sub></span> is the thickness of the weftless ply, and <span class="html-italic">D<sub>F</sub></span> is the diameter of the needled region. (<b>b</b>) Short-cut fiber ply lies between the 0° and 90° weftless plies. (<b>c</b>) The pyrolytic carbon morphology under the polarized light microscope. (<b>d</b>–<b>f</b>) The grayscale histograms of (<b>a</b>–<b>c</b>) are presented, respectively.</p> Full article ">Figure 5
<p>The schematic diagram of the tensile test of needled C/C composites.</p> Full article ">Figure 6
<p>The multiscale scheme for predicting the effective elastic properties of needled C/C composites.</p> Full article ">Figure 7
<p>(<b>a</b>) The RVE model of the weftless ply before partitioning the equivalent matrix, and (<b>b</b>) the RVE model after partitioning the equivalent matrix.</p> Full article ">Figure 8
<p>(<b>a</b>) The RVE model of the short-cut fiber ply before partitioning the equivalent matrix, and (<b>b</b>) the RVE model after partitioning the equivalent matrix.</p> Full article ">Figure 9
<p>Illustration of the RVE model of the needled fiber region.</p> Full article ">Figure 10
<p>The macroscale model of needled C/C composites.</p> Full article ">Figure 11
<p>Effects of the mesh size on (<b>a</b>) <span class="html-italic">E</span><sub>11</sub>/<span class="html-italic">E</span><sub>22</sub> and <span class="html-italic">E</span><sub>33</sub>, (<b>b</b>) <span class="html-italic">G</span><sub>12</sub> and <span class="html-italic">G</span><sub>13</sub>/<span class="html-italic">G</span><sub>23</sub>, (<b>c</b>) <span class="html-italic">ν</span><sub>12</sub> and <span class="html-italic">ν</span><sub>13</sub>/<span class="html-italic">ν</span><sub>23</sub>, and (<b>d</b>) the relative error.</p> Full article ">Figure 12
<p>Effects of the model length on (<b>a</b>) <span class="html-italic">E</span><sub>11</sub>/<span class="html-italic">E</span><sub>22</sub> and <span class="html-italic">E</span><sub>33</sub>, (<b>b</b>) <span class="html-italic">G</span><sub>12</sub> and <span class="html-italic">G</span><sub>13</sub>/<span class="html-italic">G</span><sub>23</sub>, (<b>c</b>) <span class="html-italic">ν</span><sub>12</sub> and <span class="html-italic">ν</span><sub>13</sub>/<span class="html-italic">ν</span><sub>23</sub>, and (d) the relative error.</p> Full article ">Figure 13
<p>Effects of the model thickness on (<b>a</b>) <span class="html-italic">E</span><sub>11</sub>/<span class="html-italic">E</span><sub>22</sub> and <span class="html-italic">E</span><sub>33</sub>, (<b>b</b>) <span class="html-italic">G</span><sub>12</sub> and <span class="html-italic">G</span><sub>13</sub>/<span class="html-italic">G</span><sub>23</sub>, (<b>c</b>) <span class="html-italic">ν</span><sub>12</sub> and <span class="html-italic">ν</span><sub>13</sub>/<span class="html-italic">ν</span><sub>23</sub>, and (<b>d</b>) the relative error.</p> Full article ">Figure 14
<p>Effects of porosity <span class="html-italic">V<sub>p</sub></span> on the effective elastic properties of (<b>a1</b>,<b>a2</b>) the needled region, (<b>b1</b>,<b>b2</b>) weftless ply, (<b>c1</b>,<b>c2</b>) short-cut fiber ply, and (<b>d1</b>,<b>d2</b>) needled C/C composite.</p> Full article ">Figure 14 Cont.
<p>Effects of porosity <span class="html-italic">V<sub>p</sub></span> on the effective elastic properties of (<b>a1</b>,<b>a2</b>) the needled region, (<b>b1</b>,<b>b2</b>) weftless ply, (<b>c1</b>,<b>c2</b>) short-cut fiber ply, and (<b>d1</b>,<b>d2</b>) needled C/C composite.</p> Full article ">
Open AccessArticle
Enhanced Antibacterial Activity of Carbon Dots: A Hybrid Approach with Levofloxacin, Curcumin, and Tea Polyphenols
by
Khurram Abbas, Haimei Zhu, Weixia Qin, Meiyan Wang, Zijian Li and Hong Bi
C 2024, 10(3), 84; https://doi.org/10.3390/c10030084 - 15 Sep 2024
Abstract
Bacterial infections and their increasing resistance to antibiotics pose a significant challenge in medical treatment. This study presents the synthesis and characterization of novel carbon dots (CDs) using levofloxacin (Lf), curcumin (Cur), and tea polyphenols (TP) through a facile hydrothermal method. The synthesized
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Bacterial infections and their increasing resistance to antibiotics pose a significant challenge in medical treatment. This study presents the synthesis and characterization of novel carbon dots (CDs) using levofloxacin (Lf), curcumin (Cur), and tea polyphenols (TP) through a facile hydrothermal method. The synthesized curcumin-tea polyphenol@carbon dots (Cur-TP@CDs) and levofloxacin-tea polyphenol@carbon dots (Lf-TP@CDs) were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, confirming their unique structural and chemical properties. Cur-TP@CDs exhibited an average particle size of 1.32 nanometers (nm), while Lf-TP@CDs averaged 1.58 nm. Both types demonstrated significant antibacterial activity, with Lf-TP@CDs showing superior effectiveness against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in broth dilution and disc diffusion assays. Biofilm inhibition assays revealed a significant reduction in biofilm formation at higher concentrations. The ultraviolet-visible (UV-vis) and photoluminescence (PL) spectral analyses indicated efficient photon emission, and electron paramagnetic resonance (EPR) analysis showed increased singlet oxygen generation, enhancing bactericidal effects. Live and dead bacterial staining followed by scanning electron microscopy (SEM) analysis confirmed dose-dependent bacterial cell damage and morphological deformities. These findings suggest that Cur-TP@CDs and Lf-TP@CDs are promising antibacterial agents, potentially offering a novel approach to combat antibiotic-resistant bacterial infections.
Full article
(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications)
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>(<b>a</b>) Schematic illustration of antibacterial CD synthesis from levofloxacin, curcumin, and tea polyphenols through hydrothermal method. Typical TEM images (inset: HRTEM image) and the corresponding particle size distribution histogram of (<b>b</b>) Cur-TP@CDs and (<b>c</b>) Lf-TP@CDs.</p> Full article ">Figure 2
<p>(<b>a</b>) FT–IR spectra of Cur-TP@CDs and Lf-TP@CDs. (<b>b</b>) XRD patterns of Cur-TP@CDs and Lf-TP@CDs. (<b>c</b>) XPS full-survey spectrum of Cur-TP@CDs, indicating the presence and proportion of carbon (C) nitrogen (N), and oxygen (O) with peaks corresponding to C1s, N1s, and O1s, reflecting the surface chemical composition and states. (<b>d</b>) XPS survey spectrum of LF-TP@CDs, showing the elemental composition with peaks corresponding to carbon (C1s), oxygen (O1s), nitrogen (N1s), and fluorine (F1s). The F1s peak is present but at a very low intensity, indicating that fluorine is at the detection limit.</p> Full article ">Figure 3
<p>(<b>a</b>) UV-vis absorption spectrum of Cur-TP@CDs. (<b>b</b>) Photoluminescence (PL) emission spectra of Cur-TP@CDs at different excitation wavelengths. (<b>c</b>) Time-resolved fluorescence decay profile of Cur-TP@CDs. (<b>d</b>) UV-vis absorption spectrum of Lf-TP@CDs. (<b>e</b>) PL emission spectra of Lf-TP@CDs at different excitation wavelengths. (<b>f</b>) Time-resolved fluorescence decay profile of Lf-TP@CDs.</p> Full article ">Figure 4
<p>EPR analysis of <sup>1</sup>O<sub>2</sub> generation of (<b>a</b>) Cur-TP@CDs at concentrations of 0 mg/mL, 0.125 mg/mL, 0.25 mg/mL, and 0.5 mg/mL and (<b>b</b>) Lf-TP@CDs at concentrations of 0 mg/mL, 0.125 mg/mL, 0.25 mg/mL, and 0.5 mg/mL by using TEMP as a <sup>1</sup>O<sub>2</sub> trapper.</p> Full article ">Figure 5
<p>(<b>a</b>) Survival rates of <span class="html-italic">S. aureus</span> treated with different concentrations of Lf-TP@CDs and Cur-TP@CDs. (<b>b</b>) Survival rates of <span class="html-italic">E. coli</span> treated with different concentrations of Lf-TP@CDs and Cur-TP@CDs.</p> Full article ">Figure 6
<p>Biofilm inhibition of Lf-TP@CDs and Cur-TP@CDs by (<b>a</b>) <span class="html-italic">S. aureus</span> and (<b>b</b>) <span class="html-italic">E. coli</span>.</p> Full article ">Figure 7
<p>(<b>a</b>) SEM images of <span class="html-italic">S. aureus</span> treated with different concentrations of Lf-TP@CDs and Cur-TP@CDs. (<b>b</b>) SEM images of <span class="html-italic">E. coli</span> treated with different concentrations of Lf-TP@CDs and Cur-TP@CDs.</p> Full article ">
Full article ">Figure 1
<p>(<b>a</b>) Schematic illustration of antibacterial CD synthesis from levofloxacin, curcumin, and tea polyphenols through hydrothermal method. Typical TEM images (inset: HRTEM image) and the corresponding particle size distribution histogram of (<b>b</b>) Cur-TP@CDs and (<b>c</b>) Lf-TP@CDs.</p> Full article ">Figure 2
<p>(<b>a</b>) FT–IR spectra of Cur-TP@CDs and Lf-TP@CDs. (<b>b</b>) XRD patterns of Cur-TP@CDs and Lf-TP@CDs. (<b>c</b>) XPS full-survey spectrum of Cur-TP@CDs, indicating the presence and proportion of carbon (C) nitrogen (N), and oxygen (O) with peaks corresponding to C1s, N1s, and O1s, reflecting the surface chemical composition and states. (<b>d</b>) XPS survey spectrum of LF-TP@CDs, showing the elemental composition with peaks corresponding to carbon (C1s), oxygen (O1s), nitrogen (N1s), and fluorine (F1s). The F1s peak is present but at a very low intensity, indicating that fluorine is at the detection limit.</p> Full article ">Figure 3
<p>(<b>a</b>) UV-vis absorption spectrum of Cur-TP@CDs. (<b>b</b>) Photoluminescence (PL) emission spectra of Cur-TP@CDs at different excitation wavelengths. (<b>c</b>) Time-resolved fluorescence decay profile of Cur-TP@CDs. (<b>d</b>) UV-vis absorption spectrum of Lf-TP@CDs. (<b>e</b>) PL emission spectra of Lf-TP@CDs at different excitation wavelengths. (<b>f</b>) Time-resolved fluorescence decay profile of Lf-TP@CDs.</p> Full article ">Figure 4
<p>EPR analysis of <sup>1</sup>O<sub>2</sub> generation of (<b>a</b>) Cur-TP@CDs at concentrations of 0 mg/mL, 0.125 mg/mL, 0.25 mg/mL, and 0.5 mg/mL and (<b>b</b>) Lf-TP@CDs at concentrations of 0 mg/mL, 0.125 mg/mL, 0.25 mg/mL, and 0.5 mg/mL by using TEMP as a <sup>1</sup>O<sub>2</sub> trapper.</p> Full article ">Figure 5
<p>(<b>a</b>) Survival rates of <span class="html-italic">S. aureus</span> treated with different concentrations of Lf-TP@CDs and Cur-TP@CDs. (<b>b</b>) Survival rates of <span class="html-italic">E. coli</span> treated with different concentrations of Lf-TP@CDs and Cur-TP@CDs.</p> Full article ">Figure 6
<p>Biofilm inhibition of Lf-TP@CDs and Cur-TP@CDs by (<b>a</b>) <span class="html-italic">S. aureus</span> and (<b>b</b>) <span class="html-italic">E. coli</span>.</p> Full article ">Figure 7
<p>(<b>a</b>) SEM images of <span class="html-italic">S. aureus</span> treated with different concentrations of Lf-TP@CDs and Cur-TP@CDs. (<b>b</b>) SEM images of <span class="html-italic">E. coli</span> treated with different concentrations of Lf-TP@CDs and Cur-TP@CDs.</p> Full article ">
Open AccessArticle
Emission Ellipsometry Study in Polymeric Interfaces Based on Poly(3-Hexylthiophene), [6,6]-Phenyl-C61-Butyric Acid Methyl Ester, and Reduced Graphene Oxide
by
Ana Clarissa Henrique Kolbow, Everton Crestani Rambo, Maria Ruth Neponucena dos Santos, Paulo Ernesto Marchezi, Ana Flávia Nogueira, Alexandre Marletta, Romildo Jerônimo Ramos and Eralci Moreira Therézio
C 2024, 10(3), 83; https://doi.org/10.3390/c10030083 - 11 Sep 2024
Abstract
We analyzed the interaction of three materials, reduced graphene oxide (RGO), [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and poly(3-hexylthiphene) (P3HT), as well as the dependence of its photophysical properties within the temperature range of 90 to 300 K. The nanocomposite of the
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We analyzed the interaction of three materials, reduced graphene oxide (RGO), [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and poly(3-hexylthiphene) (P3HT), as well as the dependence of its photophysical properties within the temperature range of 90 to 300 K. The nanocomposite of the films was analyzed by optical absorption ultraviolet–visible (UV-Vis) and photoluminescence (PL) and emission ellipsometry (EE) as a function of sample temperature. The surface morphology was studied by atomic force microscopy (AFM). We noted that onset levels (Eonset) of the nanocomposite of P3HT and RGO are smaller than the others. The PL spectra showed the presence of anomalies in the emission intensities in the nanocomposite of P3HT and PCBM. It was also possible to determine the electron–phonon coupling by calculating the Huang–Rhys parameters and the temperature dependence of samples. Through EE, it was possible to analyze the degree of polarization and the anisotropy. We observed a high degree of polarized emission of the P3HT films, which varies subtly according to the temperature. For nanocomposites with RGO, the polarization degree in the emission decreases, and the roughness on the surface increases. As a result, the RGO improves the energy transfer between adjacent polymer chains at the cost of greater surface roughness. Then, the greater energy transfer may favor applications of this type of nanocomposite in organic photovoltaic cells (OPVCs) with enhancement in energy conversion efficiency.
Full article
(This article belongs to the Special Issue Carbon-Based Polymer Composites: Synthesis, Processing, Characterization and Applications)
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>Chemical structure of (<b>a</b>) P3HT, (<b>b</b>) PEDOT/PSS, (<b>c</b>) RGO, and (<b>d</b>) PCBM. In Figure (<b>b</b>) “*” represents the continuation of the chain conjugation. “+” represents an electronic positive carrier charge.</p> Full article ">Figure 2
<p>Absorption spectra for samples PEDOT:PSS/P3HT:PCBM, PEDOT:PSS/P3HT:PCBM:RGO, and PEDOT:PSS/P3HT:RGO.</p> Full article ">Figure 3
<p>AFM images for samples (<b>a</b>) PEDOT:PSS/P3HT:PCBM, (<b>b</b>) PEDOT:PSS/P3HT:PCBM:RGO, and (<b>c</b>) PEDOT:PSS/P3HT:RGO. (<b>d</b>) Height distribution, (<b>e</b>) mean roughness, (<b>f</b>) skewness, and (<b>g</b>) kurtosis were calculated for the samples.</p> Full article ">Figure 4
<p>(<b>a</b>) PL spectra for samples PEDOT:PSS/P3HT:PCBM, (<b>b</b>) PEDOT:PSS/P3HT:PCBM:RGO, (<b>c</b>) PEDOT:PSS/P3HT:RGO from 90 to 300 K.</p> Full article ">Figure 5
<p>(<b>a</b>) Normalized PL spectra of samples PEDOT:PSS/P3HT:PCBM, (<b>b</b>) PEDOT:PSS/P3HT:PCBM:RGO, and (<b>c</b>) PEDOT:PSS/P3HT:RGO in different temperatures.</p> Full article ">Figure 6
<p>(<b>a</b>) Simplified schematic energy diagram for the PEDOT:PSS/P3HT:PCBM:RGO and (<b>b</b>) simplified schematic energy band diagram with E<sub>onset</sub> calculated for the PEDOT:PSS/P3HT:PCBM, PEDOT:PSS/P3HT:PCBM:RGO and PEDOT:PSS/P3HT:RGO samples at 300 K.</p> Full article ">Figure 7
<p>(<b>a</b>) EE spectra for sample PEDOT:PSS/P3HT:PCBM:RGO at 90 K and (<b>b</b>) at 300 K. (<b>c</b>) Polarization degree (P), anisotropy factors (<span class="html-italic">r</span>), and asymmetry (<span class="html-italic">g</span>), obtained from the Stokes parameters for sample PEDOT:PSS/P3HT:PCBM:RGO at 90 K and (<b>d</b>) at 300 K.</p> Full article ">Figure 8
<p>Polarization degree, P, obtained from the Stokes parameters at different temperatures for samples (<b>a</b>) PEDOT:PSS/P3HT:PCBM, (<b>b</b>) PEDOT:PSS/P3HT:PCBM:RGO, and (<b>c</b>) PEDOT:PSS/P3HT:RGO; (<b>d</b>) anisotropy factor, r, for all samples at 300 K.</p> Full article ">
Full article ">Figure 1
<p>Chemical structure of (<b>a</b>) P3HT, (<b>b</b>) PEDOT/PSS, (<b>c</b>) RGO, and (<b>d</b>) PCBM. In Figure (<b>b</b>) “*” represents the continuation of the chain conjugation. “+” represents an electronic positive carrier charge.</p> Full article ">Figure 2
<p>Absorption spectra for samples PEDOT:PSS/P3HT:PCBM, PEDOT:PSS/P3HT:PCBM:RGO, and PEDOT:PSS/P3HT:RGO.</p> Full article ">Figure 3
<p>AFM images for samples (<b>a</b>) PEDOT:PSS/P3HT:PCBM, (<b>b</b>) PEDOT:PSS/P3HT:PCBM:RGO, and (<b>c</b>) PEDOT:PSS/P3HT:RGO. (<b>d</b>) Height distribution, (<b>e</b>) mean roughness, (<b>f</b>) skewness, and (<b>g</b>) kurtosis were calculated for the samples.</p> Full article ">Figure 4
<p>(<b>a</b>) PL spectra for samples PEDOT:PSS/P3HT:PCBM, (<b>b</b>) PEDOT:PSS/P3HT:PCBM:RGO, (<b>c</b>) PEDOT:PSS/P3HT:RGO from 90 to 300 K.</p> Full article ">Figure 5
<p>(<b>a</b>) Normalized PL spectra of samples PEDOT:PSS/P3HT:PCBM, (<b>b</b>) PEDOT:PSS/P3HT:PCBM:RGO, and (<b>c</b>) PEDOT:PSS/P3HT:RGO in different temperatures.</p> Full article ">Figure 6
<p>(<b>a</b>) Simplified schematic energy diagram for the PEDOT:PSS/P3HT:PCBM:RGO and (<b>b</b>) simplified schematic energy band diagram with E<sub>onset</sub> calculated for the PEDOT:PSS/P3HT:PCBM, PEDOT:PSS/P3HT:PCBM:RGO and PEDOT:PSS/P3HT:RGO samples at 300 K.</p> Full article ">Figure 7
<p>(<b>a</b>) EE spectra for sample PEDOT:PSS/P3HT:PCBM:RGO at 90 K and (<b>b</b>) at 300 K. (<b>c</b>) Polarization degree (P), anisotropy factors (<span class="html-italic">r</span>), and asymmetry (<span class="html-italic">g</span>), obtained from the Stokes parameters for sample PEDOT:PSS/P3HT:PCBM:RGO at 90 K and (<b>d</b>) at 300 K.</p> Full article ">Figure 8
<p>Polarization degree, P, obtained from the Stokes parameters at different temperatures for samples (<b>a</b>) PEDOT:PSS/P3HT:PCBM, (<b>b</b>) PEDOT:PSS/P3HT:PCBM:RGO, and (<b>c</b>) PEDOT:PSS/P3HT:RGO; (<b>d</b>) anisotropy factor, r, for all samples at 300 K.</p> Full article ">
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