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Article

Preparation and Application of Highly Efficient Self-Cleaning Coating g-C3N4/MoS2@PDMS

by
Chunhua Gao
*,
Yifei Sima
,
Cong Xiang
and
Zerun Lv
College of Architecture and Civil Engineering, Xinyang Normal University, Xinyang 464031, China
*
Author to whom correspondence should be addressed.
Catalysts 2025, 15(1), 10; https://doi.org/10.3390/catal15010010
Submission received: 11 November 2024 / Revised: 14 December 2024 / Accepted: 19 December 2024 / Published: 26 December 2024
(This article belongs to the Special Issue Advancements in Photocatalysis for Environmental Applications)
Browse Figures
Figure 1
<p>(<b>a</b>) XRD, (<b>b</b>) Infrared spectra, and (<b>c</b>) UV-vis pattern of g-C<sub>3</sub>N<sub>4</sub>, MoS<sub>2</sub>, g/M1, g/M2, g/M3 and g/M4.</p> "> Figure 2
<p>XPS pattern of (<b>a</b>) g-C<sub>3</sub>N<sub>4</sub> and g/M3 composites; (<b>b</b>) C 1s; (<b>c</b>) N1s; (<b>d</b>) S 2p; and (<b>e</b>) Mo 3d; (<b>f</b>) N<sub>2</sub> adsorption/desorption isotherms and (inset) pore size distribution of g-C<sub>3</sub>N<sub>4</sub>/MoS<sub>2</sub> and g/M3.</p> "> Figure 3
<p>(<b>a</b>) Pseudo-first-order kinetic fitting curves for the degradation of Rhodamine in samples; (<b>b</b>) effect of capture agent on g/M3 degradation reaction; (<b>c</b>) cycling performance of g/M3.</p> "> Figure 4
<p>The preparation process of the coating. (<b>a</b>) and (<b>b</b>) are scanning electron microscope (SEM) images of the g-C<sub>3</sub>N<sub>4</sub>/MoS<sub>2</sub>@PDMS coating. (<b>c1</b>) C, (<b>c2</b>) S, and (<b>c3</b>) Si element distribution in the g-C3N4/MoS2@PDMS coating.</p> "> Figure 5
<p>Adhesion test for g-C<sub>3</sub>N<sub>4</sub>/MoS<sub>2</sub>@PDMS.</p> "> Figure 6
<p>(<b>a</b>) TGA curves of g-C<sub>3</sub>N<sub>4</sub>/MoS<sub>2</sub>@PDMS. (<b>b</b>) The degradation curve of the coating. (<b>c</b>) The degradation curve of the coating after outdoor exposure.</p> ">
Versions Notes

Abstract

:
Photocatalytic coatings are capable of achieving pollution-free degradation of organic pollutants on the surface of buildings. The preparation of photocatalytic coatings with high degradation efficiency, stability and durability constitutes a significant challenge in current widespread applications. This study prepared g-C3N4/MoS2 photocatalytic materials through a simple hydrothermal combined low-temperature calcination process, and selected the materials through characterization and photocatalytic degradation of organic wastewater experiments. Finally, poly(dimethylsiloxane) (PDMS) was added to obtain a g-C3N4/MoS2@PDMS coating. The coating was applied to the concrete surface, and, in the experiment, the coating showed good durability, stability, and high photocatalytic activity.

1. Introduction

Graphitic carbon nitride has excellent physical/chemical stability, a unique band structure, and high catalytic activity [1,2]. It has great potential in regard to the degradation of pollutants into wastewater [3]. Despite this, the g-C3N4 produced by conventional synthesis methods has a lower utilization rate of visible light, a smaller specific surface area, and fewer photogenerated electron–hole pairs, which leads to insufficient photocatalytic activity in the material [4,5]. Research often modifies g-C3N4 through element doping, combining with other semiconductor materials, and morphology control, aiming to improve its photocatalytic performance. Fellipe Magioli Cadan [6] synthesized g-C3N4 through low-temperature calcination of melamine and synthesized g-C3N4/WO3 through simple acoustic-assisted synthesis. Yu Wang [7] used L-cysteine as a precursor to prepare N and S-doped CQDs. The hydrothermal method was used to modify graphite-phase carbon nitride with NS-CQDs to form different NS-CQDs/g-C3N4 composite photocatalysts. The photocatalytic degradation efficiency of rhodamine B on NS-CQDS-modified g-C3N4 is significantly higher than that of pure g-C3N4, reaching 90.82%, which is 3.5 times higher than that of pure g-C3N4. Yixin Yuan [8] modified g-C3N4 with BiPO4 to construct an S-type heterojunction. In the methylene blue degradation experiment, BiPO4/g-C3N4 exhibited excellent photocatalytic activity. Compared with g-C3N4 and BiPO4, the modified g-C3N4 demonstrated outstanding photocatalytic activity and efficient separation of photogenerated electron–hole pairs. Owing to the synergistic effect, the modified g-C3N4 presented a high methylene blue degradation removal rate of 96.7%, which was significantly greater than that of pure g-C3N4 (46.3%) and BiPO4 (3.3%). Vadivel Saravanan and Pandian Lakshmanan modified the g-C3N4 catalytic material by surface treatment with inorganic alumina, thereby increasing its specific surface area [9]. Durga Sankar Vavilapalli and Raja Gopal Peri [10] combined brown feldspar ferrioxide KBiFe2O5 (KBFO) with graphitic carbon nitride to produce a heterojunction photocatalys, which showed an improvement in the degradation efficiency for methylene blue (MB) in the test of heterojunction catalyst. Xie and Lu [11] introduced AgO into g-C3N4. The photoelectrochemical studies confirmed that the introduction of an appropriate amount of AgO enhanced the light responsiveness of the material and the separation and transmission of photogenerated carriers. Nevertheless, with Ag being a noble metal, the high cost of the raw material has, to a certain extent, restricted the application of this material. Research has shown that metal sulfides have an appropriate band structure compared to other materials, and, due to the higher valence band formed by the S3p orbital, they have a better visible light response than many oxides. The excellent properties of sulfides make the g-C3N4/metal sulfide heterojunction system have a better photocatalytic performance [12,13]. Umair Baig [14] synthesized CdS/g-C3N4 nanocomposites by pulsed laser ablation in liquids. It was found through the degradation of wastewater experiments that there was a remarkable improvement in the photocatalytic deactivation of the material. This was attributed to the enhanced and expanded light absorption in the visible spectral region and the formation of heterojunctions between the semiconductors. Kholoud M. Alnahdi [15] developed a 3D flower-shaped sulfide of tin (3DF-SnS2) using a simplified solvothermal method which optimizes the 3DF-SnS2/g-C3N4 structure and exhibits significant Rhodamine B(RhB) degradation ability. This is mainly due to its effective ability to separate photogenerated charges as well as the harmonious synergistic effect between the 3D and 2D structures, which simplifies the charge transfer process, lowers its bandgap, and thus has a broader solar energy absorption spectrum. Due to the enhanced photocatalytic activity of the modified g-C3N4 composite photocatalyst material, its application in self-cleaning coatings is increasing. Zhao and Wu [16] used nano-graphene-like carbon nitride combined with epoxy resin to prepare a photocatalytic self-cleaning road coating. In the experiment, the coating showed good degradation effects on both gaseous and liquid pollutants. Zusheng Hang and Huili Yu [17] prepared nanoporous graphene nitride/metal–organic framework (g-C3N4/MOF) composites through solvothermal synthesis. The curing time of the UV curable coating containing g-C3N4/MOF-5 composite was significantly reduced, proving that the coating’s photocatalytic curing activity has been improved. Jiaxing Huang and Daguang Li [18] used phytate biomass and urea to successfully prepare P-doped g-C3N4 (PCN) via a one-step thermal polymerization technique which exhibited significant photocatalytic activity for the degradation of indomethacin. The degradation rate of indomethacin was 7.1 times that of the original g-C3N4 (CN). Gang Xiong and Zhanping Zhang [19] conducted thermal polymerization using urea and TiO2 nanotubes as raw materials to obtain g-C3N4/TNTs, and they subsequently introduced CNTs for compounding to obtain CNTC. The CNTC was added to PDMS to fabricate the g-C3N4/TNTs/CNTs/PDMS (CNTC/P) composite antifouling coating. The results indicated that the CNTC was successfully compounded and formed a heterogeneous structure, and the recombination rate of photogenerated carriers was decreased after compounding. The addition of CNTC to PDMS increased hydrophobicity and roughness while reducing the surface energy (SE) of the coating. Luying Sun and Yujie Tan [20] utilized the g-C3N4/TiO2 composite as the photocatalytic active component and fabricated a novel photocatalytic functional coating through medium barrier discharge (DBD) modification. The degradation efficiency of the 10%-g-C3N4/TiO2 mixed coating modified by DBD exhibited stable, persistent, and significantly higher activity. The research findings indicate that the DBD-modified g-C3N4/TiO2 successfully removed 98% of the xylene released by the fluorocarbon paint solvent within 2 h under sunlight irradiation, demonstrating enhanced sunlight capture ability and utilization efficiency along with a reduced bandgap and decreased recombination rate of electron–hole pairs.
Previous studies on the graphitic carbon nitride-based photocatalytic self-cleaning coatings have typically concentrated on the performance of the catalytic materials but overlooked the working conditions of the coatings in practical applications. Furthermore, reports on the combination of metal sulfides and graphitic carbon nitride for the preparation of coatings are extremely scarce. In this study, g-C3N4/MoS2 photocatalytic materials were prepared by a combination of hydrothermal method and low-temperature calcination, and the materials were screened by photocatalytic degradation of RhB. Then, the g-C3N4/MoS2 photocatalytic materials were modified using polydimethylsiloxane (PDMS). Finally, the modified g-C3N4/MoS2 was coated onto the substrate surface and dried to form a g-C3N4/MoS2@PDMS coating with good environmental adaptability and high photocatalytic activity. In the stability and durability test experiments conducted on this coating, it performed outstandingly. Hence, it has extensive application prospects. This coating possesses the merits of being green, low-cost, and simply fabricated. The coating still exhibits excellent degradation capability within three months under natural conditions. Therefore, it has extensive application prospects.

2. Results and Discussions

2.1. Physical Characterizations

Figure 1a shows the X-ray diffraction (XRD) pattern of the synthesized g-C3N4/MoS2 composite material. In this spectrum, the characteristic peaks of MoS2 are located at 14.5°, 34.1°, and 58.3°, which correspond to the (003) and (012) crystal planes in the MoS2 standard card (17-0744) [12], which is consistent with the reports Wang et al. [21,22]. The peak at 13.4° observed in the synthesized g-C3N4/MoS2 sample is attributed to the combined action of the (002) plane of MoS2 and the (100) plane of g-C3N4. This phenomenon may be attributed to the significant interfacial electronic coupling effect between MoS2 and g-C3N4 during the synthesis process, which leads to a change in the original structure of g-C3N4. Moreover, no impurity peaks were observed in the spectrum, indicating that the synthesized sample is a pure phase. The characteristic diffraction peaks at 2θ = 13.4° and 27.3° correspond to the (003) plane of MoS2 and the (002) plane of g-C3N4, respectively, which confirms the successful loading of MoS2 [23].
To further determine the compositions of the g-C3N4 and g-C3N4/MoS2 samples, FTIR was employed to characterize the synthesized samples. As depicted in Figure 1b, the FTIR spectrum of the g-C3N4 sample is in accordance with the classical FTIR spectrum of g-C3N4. Thus, it can be proved that the synthesized g-C3N4 is a pure phase material [24]. The absorption peak at 800 cm−1 for the four g-C3N4/MoS2 samples represents the characteristic peak of the bending vibration of carbon nitrogen rings. The absorption band ranging from 1200 to 1600 cm−1 is the stretching vibration absorption peak of the carbon nitrogen heterocycle in g-C3N4. Moreover, the absorption band from 2800 to 3400 cm−1 could be the stretching vibration of the N-H and -NH2 groups on the damaged aromatic rings at the edge of g-C3N4 or the stretching vibration of the water molecules adsorbed on its surface. By comparing the FTIR spectra of g-C3N4 and the four g-C3N4/MoS2 materials, it can be found that the transmittance of the absorption bands at 1200–1600 cm−1 and 2800–3400 cm−1 of the g-C3N4/MoS2 sample has decreased, suggesting that the infrared-light absorption ability of the sample has been enhanced after the introduction of MoS2 [25]. Figure 1c presents the UV-Vis absorption spectra of g-C3N4 and g-C3N4/MoS2 samples. It can be observed that the introduction of MoS2 leads to a gradual rightward shift in the absorption band edge of the samples, a reduction in the bandgap, and an enhancement of the visible-light absorption capacity [26].
In the XRD, FTIR, and UVRS testing processes, g/M3 exhibited a smaller bandgap and superior light absorption ability. As shown in Figure 2, the chemical composition of g-C3N4 and g/M3 materials was analyzed by XPS. The full spectrum graph (Figure 2a) of the g/M3 material indicates the presence of N, C, S, and Mo elements. The C 1s spectrum (Figure 2b) shows two peaks located at 284.8 eV and 288.4 eV, respectively, corresponding to C-C and C-N=C. As shown in Figure 2c, the C 1s spectrum is decomposed into several peaks at around 398.8 eV and 400 eV. The two peaks at 162.28 eV and 163.48 eV in binding energy are attributed to S2-ions in MoS2. The peaks at 229.2 eV and 233 eV are attributed to Mo 3d5/2 and Mo 3d3/2, respectively, and are associated with Mo4+. Figure 2f shows the N2 adsorption/desorption experimental results of g-C3N4 and g/M3. g/M3 exhibits a larger average pore size and specific surface area, with the specific surface area of g-C3N4 calculated to be 27.56 m2/g and the specific surface area of g/M3 being 167.3 m2/g. Thus, it can be seen that the treated material (g/M3) has an increased specific surface area which is approximately 6.1 times that of g-C3N4.

2.2. Analysis of Material Formation Mechanisms

2.2.1. Formation Mechanisms of MoS2

(NH4)6Mo7O24 and CH4N2S are stirred in deionized water to accelerate the dissolution process and enable the particles to integrate into the solution in the form of ions and ionic groups. In the mixed solution, a chemical reaction occurs between the molybdenum source and the sulfur source, “crystallizing” to generate intermediate products which subsequently nucleate to form the primary particles of MoS2. During the reaction process, the primary particles continuously grow and crystallize, forming MoS2 nanostructures with specific sizes and shapes. During the hydrothermal reaction, the high-temperature and high-pressure water-thermal environment within the polytetrafluoroethylene reaction liner effectively promotes the crystal growth and crystallization of MoS2. After the reaction is completed, the reaction vessel is retrieved, and the sample is washed to remove excess solution and impurities, followed by drying to obtain powdered MoS2.

2.2.2. Formation Mechanisms of g-C3N4/MoS2

Upon heating, urea initially undergoes a hydrolysis reaction, generating ammonium carbamate and carbon dioxide. The ammonium carbamate resulting from the hydrolysis further decomposes to yield ammonia and carbon dioxide. Ammonia and other nitrogen-containing compounds undergo polycondensation reactions under high-temperature conditions to form carbon nitride and other products. MoS2 (molybdenum disulfide) interacts between the layers of g-C3N4 at elevated temperatures, constructing a heterostructure that enhances the separation efficiency of photogenerated charges, ultimately forming g-C3N4/MoS2.

2.2.3. Formation Mechanisms of g-C3N4/MoS2@PDMS

PDMS, as an elastic material of non-polar polymers, exhibits outstanding chemical stability. Its incorporation significantly enhances the mechanical properties of the g-C3N4/MoS2 composite material, making it more resistant to wear and abrasion, strengthening its durability in practical applications and consequently improving the availability and lifespan of the photocatalyst.

2.3. Photocatalytic Properties

The pseudo-first-order kinetic plots of the degradation of Rhodamine B by g-C3N4 and g-C3N4/MoS2 samples under visible light are shown in Figure 3a. From Figure 3a, it can be seen that, compared with g-C3N4, the g-C3N4/MoS2 samples with MoS2 addition all exhibit higher catalytic efficiency. Among them, the absolute value of the rate constant k for g/M3 is the largest, about three times that of g-C3N4, indicating that the g/M3 sample has the highest degradation efficiency. To determine the active intermediates that lead to the high catalytic activity of the g/M3 samples, and to explore the working mechanism of the g/M3-catalyzed degradation of pollutants, benzoquinone (BQ) was selected as the scavenger for ·O2−, isopropanol (IPA) as the scavenger for OH, and EDTA-2Na as the scavenger for h+ in the photocatalytic reaction. The test results of the active species in the photocatalytic reaction are presented in Figure 3b. After the addition of IPA, the photocatalytic activity of g/M3 for the degradation of RhB was scarcely affected, whereas, upon the addition of BQ, the degradation reaction of RhB by g/M3 was significantly inhibited, and its degradation efficiency decreased to 21%. The inhibitory effect of EDTA-2Na on the degradation reaction was less than that of BQ, and its degradation efficiency dropped to 47%. It can be concluded from the above analysis that, in the photocatalytic degradation of RhB by g/M3, the main active species are ·O2− and photogenerated h+, among which O2− plays the most crucial role. Excellent stability is a key criterion for evaluating the overall performance of a photocatalyst. Figure 3c shows that, after 30 cycles of reuse, the sample maintained a RhB degradation rate above 70%, indicating its strong photocatalytic stability [27,28,29].

2.4. Performance of Photocatalytic Coating

Figure 4 illustrates the preparation process of the g-C3N4/MoS2@PDMS coating. As depicted in Figure 4a, the coating exhibits a relatively uniform distribution across the substrate surface. Upon magnification of a localized area, it is evident that the catalyst within the coating possesses an extensive surface area and a well-defined morphology. Studies indicate that maximizing catalyst exposure enhances reaction efficiency [30,31]. The surface elemental analysis of the g-C3N4/MoS2@PDMS coating, as shown in Figure 4(c1–c3), shows that C, S, and Si elements are evenly distributed in the coating, verifying the successful synthesis of the coating.
The coating is applied to the concrete surface, and the adhesion of the coating is tested according to the standard ISO 2409:2020 [32] using the grid test method. A white steel scriber is used to make scratches on the concrete coating surface to form a grid pattern. After sweeping the grid diagonally with a brush, 3M of tape is applied directly over the grid position and immediately peeled off. The grid area is enlarged using a magnifying glass. The experimental results are shown in Figure 5, where the coating with PDMS preparation shows less coating loss and a more uniform coating after tape adhesion compared to the control group with direct brush coating of the catalytic material. This demonstrates that the use of PDMS enhances the adhesion of the coating to the substrate.
As depicted in Figure 6a, within the temperature range from 100 °C to approximately 500 °C, the thermogravimetric analysis (TGA) curve remains relatively stable, suggesting that the coating exhibits excellent thermal stability within this temperature range. Between 500 °C and 600 °C, a significant drop is observed in the thermogravimetric curve, suggesting that the coating undergoes a principal decomposition process within this temperature range. It is hypothesized that the mass loss during this period is due to the thermal decomposition of graphitic carbon nitride. Beyond 600 °C, the thermogravimetric curve becomes stable, postulating that the residue at this moment is MoS2. The stable mass of the residue implies that the coating still maintains a certain level of stability at high temperatures. Overall, the coating exhibits excellent thermal stability [33]. The degradation performance of g-C3N4/MoS2@PDMS was compared with those of g-C3N4 and MoS2. g-C3N4/MoS2@PDMS demonstrated a catalytic degradation performance twice as high as that of g-C3N4 and MoS2. The degradation rate could reach 74% within 6 min (excluding adsorption and degradation in the dark reaction). Separate degradation experiments were conducted on the coating placed outdoors for two months before and after. As shown in Figure 6c, the g-C3N4/MoS2@PDMS still demonstrated the degradation ability towards Rhodamine B after two months of outdoor exposure, reaching 84% of the degradation ability of the unexposed coating (Figure 6b), which proves that this material possesses excellent stability. It is notable that the adsorption/degradation capacity of the coating placed outdoors decreased significantly in the photocatalytic dark reaction stage. Under the same experimental conditions, it only reached 35% of the untreated coating. Based on the experimental conditions, it is hypothesized that the adsorption of some dust particles during outdoor placement resulted in this. The experimental results show that the g-C3N4/MoS2@PDMS exhibits better adhesion and higher thermal stability in practical applications. The raw materials for the coating are cheap and readily available, the process is simple, and there is no pollution. Therefore, it has broad practical application prospects [34,35].

3. Experimental

3.1. Materials

The Rhodamine B, PDMS (polydimethylsiloxane), and Thiourea (CH4N2S) were purchased from Shanghai McLin Biochemical Technology Co., Ltd. (Shanghai McLin Biochemical Technology Co., Ltd., Shanghai, China). The (NH4)6Mo7O24·4H2O, urea, and acetone were purchased from Guoyao Group Chemical Reagents Co., Ltd. (Sinopharm Chemical Reagent Co., Ltd., Shanghai, China). The reagents were all of analytical purity and could be used directly.

3.2. Synthesize of Photocatalyst

3.2.1. Synthesize of MoS2

Weigh 360 mg of (NH4)6Mo7O24 and 665 mg of CH4N2S, then dissolve them in 30 mL of deionized water. Stir the mixture for 5 min using a magnetic stirrer. Transfer the solution to a hydrothermal reactor and heat it at 230 °C for 24 h. Afterward, wash the black powder with water and ethanol multiple times, then dry it at 60 °C to obtain MoS2.

3.2.2. Synthesize of g-C3N4/MoS2

Take 3 mg of the obtained MoS2 and thoroughly mix it with 5 g of CH4N2O. Grind the mixture in an agate mortar for 30 min, then add 2 mL of deionized water to stir evenly. Pour the mixture into a shallow dish and dry it at 60 °C, followed by grinding and transferring into a crucible. Heat up to 550 °C for 240 min at a rate of 5 °C/min in N2. After naturally cooling to room temperature, remove the samples from the crucible and ground for 30 min to obtain a light-yellow powder, designated as g-C3N4/MoS2 or g/M1. For a comparative analysis, an identical method was employed to blend 5 g of CH4N2O with 6, 12, and 24 mg of MoS2, obtaining the samples of g/M2, g/M3, and g/M4, respectively.

3.2.3. Preparation of Photocatalytic Coating

After grinding 100 mg of the catalytic material for 30 min, 10 mL of acetone solution was added and homogeneously mixed. Subsequently, 10 mL of a 10% PDMS solution prepared with ethanol was introduced and uniformly stirred. The resultant mixture was thinly coated onto a glass slide and placed in an oven at 50 °C for 3 h to obtain g-C3N4/MoS2@PDMS self-cleaning coating.

3.3. Characterization Techniques

The crystal structure of the samples was analyzed using a Miniflex X-ray diffractometer (Rigaku Corporation, Tokyo, Japan). The changes in functional groups and chemical bonds were analyzed using a Tensor 27 Fourier transform infrared spectrometer (BRUKER AXS GMBH, Karlsruhe, Germany). The micromorphology of the coating was observed by an S4800 scanning electron microscope (Hitachi, Chiyoda-ku, Japan). The UV-Vis absorption spectra of the samples were acquired using a DR-6000 (HACH, Berlin, Germany) ultraviolet-visible spectrophotometer. The specific surface area and pore size distribution of the samples were analyzed using the ASAP 2460 physical adsorption analyzer (BET) by Instrument Corp. (Amherst, NY, USA). A thermogravimetric analysis was carried out using the TGA55 model instrument produced by the American TA Company (New Castle, DE, USA) and conducted under an air atmosphere.

3.4. Photocatalytic Experiment

The photocatalytic reaction is conducted in a low-temperature constant-temperature chamber. In the photocatalytic experiment, PLS-SXE300+ Xenon (PERFECT LIGHT, Beijing, China) was utilized to simulate the solar light source for the visible light catalytic degradation experiment and a 10 mg/mL Rhodamine B (RhB) solution was employed as the degradation substrate. For each degradation experiment, 100 mL of substrate solution was used, and the g-C3N4/MoS2@PDMS coating dried on aluminum foil was selected for the catalytic degradation experiments. To assess the long-term stability of the catalytic coating in the natural environment, the degradation performance before and after two months of outdoor placement was compared, and the adhesion of the coating was tested via grid cutting experiments.

4. Conclusions

In this study, a series of g-C3N4/MoS2 photocatalytic materials were successfully fabricated by the hydrothermal method combined with low-temperature calcination. The introduction of MoS2 significantly enhanced the absorption capacity of visible light by g-C3N4, thereby improving the catalytic activity of the catalyst. Using Rhodamine B as the substrate, the degradation tests were carried out on the materials, and the g-C3N4/MoS2 with a MoS2 doping amount of 12 mg exhibited excellent catalytic effects. The g-C3N4/MoS2@PDMS coating was obtained by introducing polydimethylsiloxane for modification based on g/M3. The introduction of polydimethylsiloxane significantly enhanced the adhesion of the coating. The coating showed high catalytic activity in the degradation experiment, and it still had a self-cleaning ability after three months in natural conditions, indicating that the coating had good durability and stability. The raw materials for the coating are cheap and readily available; the process is simple, there is no pollution, and it has broad practical application prospects.

Author Contributions

Conceptualization, C.G.; methodology, C.G.; validation, C.X.; resources, C.G.; data curation, Y.S.; writing—original draft preparation, Z.L. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Youth Innovation and Entrepreneurship Training Program for College Students in Henan Province, grant number 202410477018.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. (a) XRD, (b) Infrared spectra, and (c) UV-vis pattern of g-C3N4, MoS2, g/M1, g/M2, g/M3 and g/M4.
Figure 1. (a) XRD, (b) Infrared spectra, and (c) UV-vis pattern of g-C3N4, MoS2, g/M1, g/M2, g/M3 and g/M4.
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Figure 2. XPS pattern of (a) g-C3N4 and g/M3 composites; (b) C 1s; (c) N1s; (d) S 2p; and (e) Mo 3d; (f) N2 adsorption/desorption isotherms and (inset) pore size distribution of g-C3N4/MoS2 and g/M3.
Figure 2. XPS pattern of (a) g-C3N4 and g/M3 composites; (b) C 1s; (c) N1s; (d) S 2p; and (e) Mo 3d; (f) N2 adsorption/desorption isotherms and (inset) pore size distribution of g-C3N4/MoS2 and g/M3.
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Figure 3. (a) Pseudo-first-order kinetic fitting curves for the degradation of Rhodamine in samples; (b) effect of capture agent on g/M3 degradation reaction; (c) cycling performance of g/M3.
Figure 3. (a) Pseudo-first-order kinetic fitting curves for the degradation of Rhodamine in samples; (b) effect of capture agent on g/M3 degradation reaction; (c) cycling performance of g/M3.
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Figure 4. The preparation process of the coating. (a) and (b) are scanning electron microscope (SEM) images of the g-C3N4/MoS2@PDMS coating. (c1) C, (c2) S, and (c3) Si element distribution in the g-C3N4/MoS2@PDMS coating.
Figure 4. The preparation process of the coating. (a) and (b) are scanning electron microscope (SEM) images of the g-C3N4/MoS2@PDMS coating. (c1) C, (c2) S, and (c3) Si element distribution in the g-C3N4/MoS2@PDMS coating.
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Figure 5. Adhesion test for g-C3N4/MoS2@PDMS.
Figure 5. Adhesion test for g-C3N4/MoS2@PDMS.
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Figure 6. (a) TGA curves of g-C3N4/MoS2@PDMS. (b) The degradation curve of the coating. (c) The degradation curve of the coating after outdoor exposure.
Figure 6. (a) TGA curves of g-C3N4/MoS2@PDMS. (b) The degradation curve of the coating. (c) The degradation curve of the coating after outdoor exposure.
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MDPI and ACS Style

Gao, C.; Sima, Y.; Xiang, C.; Lv, Z. Preparation and Application of Highly Efficient Self-Cleaning Coating g-C3N4/MoS2@PDMS. Catalysts 2025, 15, 10. https://doi.org/10.3390/catal15010010

AMA Style

Gao C, Sima Y, Xiang C, Lv Z. Preparation and Application of Highly Efficient Self-Cleaning Coating g-C3N4/MoS2@PDMS. Catalysts. 2025; 15(1):10. https://doi.org/10.3390/catal15010010

Chicago/Turabian Style

Gao, Chunhua, Yifei Sima, Cong Xiang, and Zerun Lv. 2025. "Preparation and Application of Highly Efficient Self-Cleaning Coating g-C3N4/MoS2@PDMS" Catalysts 15, no. 1: 10. https://doi.org/10.3390/catal15010010

APA Style

Gao, C., Sima, Y., Xiang, C., & Lv, Z. (2025). Preparation and Application of Highly Efficient Self-Cleaning Coating g-C3N4/MoS2@PDMS. Catalysts, 15(1), 10. https://doi.org/10.3390/catal15010010

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