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CN104458829A - NO2 gas sensor based on rod-cluster In2O3 nanometer sensitive material and preparation method thereof - Google Patents

NO2 gas sensor based on rod-cluster In2O3 nanometer sensitive material and preparation method thereof Download PDF

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Publication number
CN104458829A
CN104458829A CN201510003593.1A CN201510003593A CN104458829A CN 104458829 A CN104458829 A CN 104458829A CN 201510003593 A CN201510003593 A CN 201510003593A CN 104458829 A CN104458829 A CN 104458829A
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sensitive material
ceramic pipe
gas sensor
sensor
cluster shape
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卢革宇
李晓伟
孙鹏
刘凤敏
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Jilin University
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Jilin University
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Abstract

The invention belongs to the technical field of semiconductor oxide gas sensors and particularly relates to a NO2 gas sensor based on a rod-cluster In2O3 nanometer sensitive material and a preparation method of the NO2 gas sensor. The whole technological process comprises the two aspects of synthesis of the In2O3 nanometer material and manufacturing of the NO2 gas sensor. According to the preparation method, firstly, the rod-cluster In2O3 gas sensitive material is prepared successfully by combining a microwave hydrothermal method and a calcination method. The synthesis method has the advantages that operation is easy, productivity is high, repeatability is good, energy is saved, high efficiency is achieved, and cost is low, and therefore the synthesis method is suitable for scale production. In addition, based on the synthesized In2O3 material, a traditional indirect-heating device structure is adopted to construct the NO2 gas sensor. Research shows that the sensor can excellently respond to NO2; more importantly, this type of sensor is small in size and low in cost and shows very broad application prospect with respect to NO2 monitoring.

Description

Based on cluster shape In 2o 3the NO of nano sensitive material 2gas sensor and preparation method thereof
Technical field
The invention belongs to conductor oxidate gas sensor technical field, be specifically related to a kind of based on cluster shape In 2o 3the NO of nano sensitive material 2sensor and preparation method thereof, preparation method comprises In 2o 3the synthesis of nano sensitive material and NO 2making two aspects of gas sensor.
Background technology
Nitrogen dioxide is a kind of typical oxidizing gas, can cause the harm such as acid rain and photo-chemical smog, cause serious loss and destruction to the productive life of people.Especially in the last few years, along with improving constantly of industrialization degree, in air, the discharge capacity of nitrogen dioxide increases year by year, and nitrogen dioxide has now become one of main pollutant in atmospheric environment.In order to contain the further deterioration of atmospheric environment, in Real-Time Monitoring air, the content of nitrogen dioxide is extremely urgent.And the accurate measurements that will realize nitrogen dioxide, just need the support of the gas sensor of some dependable performances.So, be fundamentally to develop a kind of high performance gas sensitive material.
In 2o 3as a kind of important N-shaped oxide semiconductor material, there is very high conductivity, good selectivity and high response can be shown to oxidizing gas, be therefore considered to a kind of desirable sensitive material.In order to optimize its gas sensitization characteristic, the In of various different-shape 2o 3successively be synthesized.But, most of In 2o 3synthetic method relative complex, productive rate is lower, is difficult to be applied to, in the middle of suitability for industrialized production, greatly constraining In 2o 3the development of base gas sensor.
Along with the progress of material science and the ripe day by day of instrument manufacturing, up to the present, existing a lot of material preparation method is used to the nano material of synthesizing various different geometry and pattern.Such as, thermal evaporation, chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD), ullrasonic spraying and electrostatic spinning etc.But there is much serious deficiency in these synthetic methods above-mentioned self.In general, these methods all need loaded down with trivial details operation steps, a large amount of energy resource consumptions, the participation of toxic reagent and the experiment condition of harshness.Therefore, for above shortcomings in these methods, a kind of method finding simple and effective, environmental protection still tool is of great significance.In the last few years, the preparation developing into nano material of microwave chemical was filled with new vitality.Microwave can not only provide the heating source of uniform high-efficiency, promptly increases the temperature of whole reaction system, simultaneously because its thermal inertia is less, whole heating process can also be made to be under accurately control.Therefore, have reason to believe, use microwave assisted synthesizing method can prepare high-quality micro-nano functional material at short notice.
Summary of the invention
The present invention is intended to the deficiency for existing in above-mentioned many preparation method of nano material, provides a kind of energy-efficient, simply controlled nano material synthetic method, and the cluster shape indium sesquioxide that this preparation method synthesizes is used as NO 2gas sensitive material constructs gas sensor further.The In that the method is obtained 2o 3there is homogeneous pattern and size, and can to NO 2gas meter reveals excellent gas-sensitive property.
The present invention first with inidum chloride, urea and vitamin C for the raw material that sets out, utilize microwave-hydrothermal method (10 ~ 60min) within very short time successfully to prepare the persursor material of cluster shape indium oxide.Then, the In of pure phase is obtained through calcining 2o 3.Finally, the In of gained is utilized 2o 3as gas sensitive material, make heater-type resistor-type gas sensor.
Heater-type gas sensor configuration of the present invention, by an outside surface with two parallel, ring-types and the ceramic pipe substrate of gold electrode separate, the cluster shape In be coated on ceramic pipe outside surface and gold electrode 2o 3sensitive material, be placed in nickel-chrome heater strip in ceramic pipe and device base composition; Nickel-chrome heater strip passes to direct current to provide the working temperature of sensor, realizes measuring NO by the direct current resistance resistance measured in different atmosphere between two gold electrodes 2the function of concentration; Wherein, cluster shape In 2o 3nano sensitive material is prepared by following steps:
1. by 0.5 ~ 3mmol tetra-chloride hydrate indium (InCl 34H 2o) and 1 ~ 6mmol urea (CO (NH 2) 2) join the dissolving of 30 ~ 60mL deionized water for stirring successively, after clear transparent solutions to be formed, the vitamin C of 0.03 ~ 0.5mmol is added in above-mentioned mixed solution, continue to keep stirring 15 ~ 30min;
2. the mixed solution obtained is transferred in microwave reaction kettle, and be positioned in microwave hydrothermal stove; Microwave heating time is set to 10 ~ 60min, and target temperature is set to 110 ~ 180 DEG C;
3. until after reaction system is cooled to room temperature, by the product deionized water in reactor and ethanol alternating centrifugal washing 3 ~ 8 times, the survivor ion in reaction solution is washed off;
4. the product after washing is dried under 60 ~ 80 DEG C of conditions, subsequently dried powder is calcined 2 ~ 5 hours under 450 ~ 600 DEG C of conditions, be then naturally down to room temperature, obtain sensitive material; Cluster shape In under electron microscope 2o 3become approximates axial symmetry, length is 1 ~ 3 μm, and the diameter of each rod is 30 ~ 100nm.
One of the present invention is based on cluster shape In 2o 3the NO of sensitive material 2gas sensor, its preparation process is as follows:
1. 15 ~ 40mg In is got 2o 3powder puts into mortar, then adds 100 ~ 500 μ L deionized waters, grinds its furnishing pasty slurry gently, then with fine, soft fur brush, above-mentioned slurry is coated in Al equably 2o 3the outside surface of ceramic pipe substrate; Ceramic pipe internal diameter used is 0.6 ~ 0.9mm, and external diameter is 1 ~ 1.2mm, and length is 2 ~ 6mm; The two ends of ceramic pipe outside surface are respectively with an annular gold electrode, and electrode width is 0.5 ~ 0.8mm, each electrode all connect two Pt silks and make pin; Al after coating 2o 3outside surface and the annular gold electrode of ceramic pipe substrate are covered by sensitive material completely, only reserve pin stand-by;
2. the ceramic pipe substrate with sensitive material is placed on below infrared lamp and toasts 20 ~ 30min, then ceramic pipe substrate is calcined 2 ~ 4 hours at 400 ~ 500 DEG C; The thickness of the sensitive material obtained is 10 ~ 30 μm;
3. at room temperature, be that the nickel-chrome heater strip of 40 ~ 60 Ω penetrates from ceramic tube inside by resistance value, be used for providing required working temperature to the sensitive material on ceramic pipe surface with this; Finally all external pins are welded on device base, just obtain In through encapsulation 2o 3base NO 2gas sensor.
In 2o 3base NO 2the principle of work of gas sensor:
When gas sensor is placed in air, some oxygen molecules can be adsorbed in sensitive material surface, these oxygen molecules can from sensitive material abstracting moiety electronics, and with O 2 -, O -or O 2-in is present in etc. form 2o 3surface, In 2o 3sensitive material surface then forms a depleted of electrons layer, and now the resistance of sensor is designated as R a; If there is NO in the surrounding of sensor 2during gas molecule, NO 2molecule can be adsorbed on sensitive material surface equally, due to NO 2gas molecule has extremely strong takes electronic capability by force, and more electrons is by NO 2seize, thus make In 2o 3the depleted of electrons layer width on surface increases further, and correspondingly, the resistance of sensor also can increase and (is designated as R g).So, just can NO around determination sensor by the change of survey sensor resistance 2the concentration of gas molecule.The Calculation of Sensitivity formula of sensor is S=R g/ R a.
Advantage of the present invention is:
(1) the way utilizing microwave hydrothermal to combine with calcining has just prepared the In of the pure phase with specific morphology within very short time 2o 3powder.This synthetic method is simple to operate, productive rate is high, favorable repeatability, efficient energy-saving, with low cost, be suitable for large-scale production.
(2) gas sensor manufacture craft is simple, and cost is low, and volume is little, and energy consumption is low, at NO 2gas sensor aspect has very important theory and actual application value.
Accompanying drawing explanation
Fig. 1: the cluster shape In in embodiment 1 2o 3electron scanning (SEM) photo under low enlargement ratio.
Fig. 2: the cluster shape In in embodiment 1 2o 3electron scanning (SEM) photo under high magnification.
Fig. 3: cluster shape In in embodiment 1 2o 3xRD spectra.
Fig. 4: (a) is based on In 2o 3the NO of sensitive material 2the structural representation of sensor; (b) base schematic diagram.
Fig. 5: cluster shape In in embodiment 1 2o 3nitrogen adsorption desorption curve.
Fig. 6: the NO in embodiment 1 2sensor when working temperature is 100 DEG C to the sensitivity of gas with various.
As shown in Figure 1, in embodiment 1, the microscopic appearance of product is cluster shape In 2o 3, cluster shape In 2o 3size Distribution is between 1.5 ~ 2 μm, and particle dispersion is better.
As shown in Figure 2, each cluster shape In 2o 3the nanometer rods composition of 50 ~ 80nm is about by many diameters, and the distribution of overall one-tenth approximates axial symmetry.
As shown in Figure 3, by contrasting with the XRD spectra of standard, the product obtained in embodiment 1 belongs to the In of pure phase 2o 3, exist without other assorted peaks.
As shown in Figure 4, the NO in embodiment 1 2sensor is by In 2o 3sensitive material 403, Al 2o 3ceramic pipe substrate 401, annular gold electrode 402, Pt silk 404, nichrome coils 405 and device base 406 6 core component compositions.
As shown in Figure 5, the cluster shape In of embodiment 1 2o 3there is obvious nitrogen adsorption desorption winding.
As shown in Figure 6, when device works under optimum working temperature (100 DEG C), the sensor in embodiment 1 is to NO 2gas meter reveals extraordinary selectivity, and to 1ppm NO 2sensitivity can reach 87.
Embodiment
Embodiment 1:
Microwave-hydrothermal method is utilized to synthesize In 2o 3sensitive material also makes NO 2gas sensor, its specific implementation process is as follows:
(1) by 1mmol tetra-chloride hydrate indium (InCl 34H 2and 5mmol urea (CO (NH O) 2) 2) join the dissolving of 30mL deionized water for stirring successively, after clear transparent solutions to be formed, the vitamin C of 0.125mmol is added in above-mentioned mixed solution, continue to keep stirring 15min;
(2) the mixed solution obtained is transferred in 100mL microwave reaction kettle, and be positioned in microwave hydrothermal stove; Microwave heating time is set to 30min, and target temperature is set to 140 DEG C;
(3) until after reaction system is cooled to room temperature, the product deionized water in reactor and ethanol alternating centrifugal washed 5 times, washes the survivor ion in reaction solution off;
(4) the product after washing is transferred in 80 DEG C of baking ovens and dry, subsequently dried powder is put into muffle furnace and calcine.Calcine two hours under 550 DEG C of conditions, be then naturally down to room temperature, obtain final sensitive material;
(5) get appropriate In 2o 3powder (about 20mg) puts into mortar, then adds 200 μ L deionized waters, grinds its furnishing pasty slurry gently, then with fine, soft fur brush, above-mentioned slurry is coated in Al equably 2o 3the outside surface of ceramic pipe substrate; Ceramic pipe internal diameter used is 0.8mm, external diameter 1.2mm, and long is 4mm; Respectively there is an annular gold electrode at ceramic pipe two ends, and electrode width is 0.6mm, each electrode all connect two Pt silks and make pin, the Al after coating 2o 3outside surface and the annular gold electrode of ceramic pipe substrate are covered by sensitive material completely, only reserve pin stand-by;
(6) the ceramic pipe substrate with sensitive material is placed on below infrared lamp and toasts 25min, then ceramic pipe substrate is put into muffle furnace and calcine 2 hours at 400 DEG C; The thickness of the sensitive material obtained is about 20 μm;
(7) be down to after room temperature until muffle furnace, take out ceramic pipe substrate; The NI-G coil being about 40 Ω by a resistance value penetrates from ceramic tube inside, and being used for provides required working temperature to the sensitive material on ceramic pipe surface; Finally all external pins are welded on device base, just obtain In through simple encapsulation 2o 3base NO 2gas sensor.

Claims (4)

1. one kind based on cluster shape In 2o 3the NO of nano sensitive material 2sensor, is characterized in that: be with two parallel, ring-types and the ceramic pipe substrate of gold electrode separate, the cluster shape In be coated on ceramic pipe outside surface and gold electrode by an outside surface 2o 3sensitive material, be placed in nickel-chrome heater strip in ceramic pipe and device base composition; Nickel-chrome heater strip passes to direct current to provide the working temperature of sensor, realizes measuring NO by the direct current resistance resistance measured in different atmosphere between two gold electrodes 2the function of concentration; Wherein, cluster shape In 2o 3nano sensitive material is prepared by following steps,
1. 0.5 ~ 3mmol tetra-chloride hydrate indium and 1 ~ 6mmol urea are joined successively 30 ~ 60mL deionized water for stirring to dissolve, after clear transparent solutions to be formed, the vitamin C of 0.03 ~ 0.5mmol is added in above-mentioned mixed solution, continue to keep stirring 15 ~ 30min;
2. the mixed solution obtained is transferred in microwave reaction kettle, and be positioned in microwave hydrothermal stove; Microwave heating time is set to 10 ~ 60min, and target temperature is set to 110 ~ 180 DEG C;
3. until after reaction system is cooled to room temperature, by the product deionized water in reactor and ethanol alternating centrifugal washing 3 ~ 8 times, the survivor ion in reaction solution is washed off;
4. the product after washing is dried under 60 ~ 80 DEG C of conditions, subsequently dried powder is calcined 2 ~ 5 hours under 450 ~ 600 DEG C of conditions, be then naturally down to room temperature, obtain sensitive material.
2. as claimed in claim 1 a kind of based on cluster shape In 2o 3the NO of nano sensitive material 2sensor, is characterized in that: ceramic pipe internal diameter is 0.6 ~ 0.9mm, and external diameter is 1 ~ 1.2mm, and length is 2 ~ 6mm; The width of annular gold electrode is 0.5 ~ 0.8mm; The thickness of sensitive material is 10 ~ 30 μm; The resistance value of nickel-chrome heater strip is 40 ~ 60 Ω.
3. one according to claim 1 is based on cluster shape In 2o 3the NO of sensitive material 2the preparation method of gas sensor, its step is as follows:
1. by cluster shape In 2o 3the responsive furnishing pasty slurry of nanometer, is then coated in Al equably by above-mentioned slurry 2o 3the outside surface of ceramic pipe substrate; The two ends of ceramic pipe outside surface, respectively with an annular gold electrode, each electrode all connect two Pt silks and make pin; Al after coating 2o 3outside surface and the annular gold electrode of ceramic pipe substrate are covered by sensitive material completely, only reserve pin stand-by;
2. the ceramic pipe substrate with sensitive material is placed on below infrared lamp and toasts 20 ~ 30min, then ceramic pipe substrate is calcined 2 ~ 4 hours at 400 ~ 500 DEG C;
3. at room temperature, nickel-chrome heater strip is penetrated from ceramic tube inside; Finally all external pins are welded on device base, just obtain In through encapsulation 2o 3base NO 2gas sensor.
4. as claimed in claim 3 a kind of based on cluster shape In 2o 3the NO of sensitive material 2the preparation method of gas sensor, is characterized in that: step 1. in be by 15 ~ 40mg In 2o 3powder puts into mortar, then adds 100 ~ 500 μ L deionized waters, grinds its furnishing pasty slurry gently.
CN201510003593.1A 2015-01-05 2015-01-05 NO2 gas sensor based on rod-cluster In2O3 nanometer sensitive material and preparation method thereof Pending CN104458829A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105424764A (en) * 2015-11-05 2016-03-23 吉林大学 Nitrogen dioxide sensor based on orderly-channel Ni-doped mesoporous indium oxide and preparation method thereof
CN105866191A (en) * 2016-06-08 2016-08-17 吉林大学 Zr-doped mesoporous oxide indium nitrogen dioxide sensor based on pore passage order and preparation method thereof
CN108195894A (en) * 2017-12-26 2018-06-22 桂林理工大学 Air-sensitive coating for monitoring CO, NO2 content in alcohol-based fuel tail gas in real time and preparation method thereof
CN108398464A (en) * 2018-03-10 2018-08-14 吉林大学 A kind of H2S sensors and preparation method thereof based on hollow spherical structure La doped indium oxide nano sensitive materials
CN110261445A (en) * 2019-07-12 2019-09-20 东北大学 One kind growing nanometer In based on nonmetallic mineral electrode substrate surface in situ2O3Room temperature NO2Sensor and preparation method
CN112557458A (en) * 2020-12-04 2021-03-26 江南大学 Preparation method of indium oxide nanowire and NO containing indium oxide nanowire2Method for manufacturing sensor and sensor

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105424764A (en) * 2015-11-05 2016-03-23 吉林大学 Nitrogen dioxide sensor based on orderly-channel Ni-doped mesoporous indium oxide and preparation method thereof
CN105866191A (en) * 2016-06-08 2016-08-17 吉林大学 Zr-doped mesoporous oxide indium nitrogen dioxide sensor based on pore passage order and preparation method thereof
CN108195894A (en) * 2017-12-26 2018-06-22 桂林理工大学 Air-sensitive coating for monitoring CO, NO2 content in alcohol-based fuel tail gas in real time and preparation method thereof
CN108195894B (en) * 2017-12-26 2021-01-15 桂林理工大学 Gas-sensitive coating for monitoring CO and NO2 contents in tail gas of alcohol-based fuel and preparation method thereof
CN108398464A (en) * 2018-03-10 2018-08-14 吉林大学 A kind of H2S sensors and preparation method thereof based on hollow spherical structure La doped indium oxide nano sensitive materials
CN110261445A (en) * 2019-07-12 2019-09-20 东北大学 One kind growing nanometer In based on nonmetallic mineral electrode substrate surface in situ2O3Room temperature NO2Sensor and preparation method
CN112557458A (en) * 2020-12-04 2021-03-26 江南大学 Preparation method of indium oxide nanowire and NO containing indium oxide nanowire2Method for manufacturing sensor and sensor

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