CN114988460A - Indium oxide nano material and application thereof - Google Patents
Indium oxide nano material and application thereof Download PDFInfo
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- CN114988460A CN114988460A CN202210788814.0A CN202210788814A CN114988460A CN 114988460 A CN114988460 A CN 114988460A CN 202210788814 A CN202210788814 A CN 202210788814A CN 114988460 A CN114988460 A CN 114988460A
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- 229910003437 indium oxide Inorganic materials 0.000 title claims abstract description 87
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 title claims abstract description 87
- 239000002086 nanomaterial Substances 0.000 title claims abstract description 42
- 239000007789 gas Substances 0.000 claims abstract description 41
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910000037 hydrogen sulfide Inorganic materials 0.000 claims abstract description 22
- 238000000034 method Methods 0.000 claims abstract description 13
- 238000001514 detection method Methods 0.000 claims abstract description 6
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 claims description 46
- 238000003756 stirring Methods 0.000 claims description 28
- 238000006243 chemical reaction Methods 0.000 claims description 25
- 239000000463 material Substances 0.000 claims description 19
- 238000010438 heat treatment Methods 0.000 claims description 18
- ZYYDOSLSINDXIQ-UHFFFAOYSA-N O.O.O.O.[In+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O Chemical compound O.O.O.O.[In+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O ZYYDOSLSINDXIQ-UHFFFAOYSA-N 0.000 claims description 16
- 238000001816 cooling Methods 0.000 claims description 16
- 229910001429 cobalt ion Inorganic materials 0.000 claims description 10
- XLJKHNWPARRRJB-UHFFFAOYSA-N cobalt(2+) Chemical compound [Co+2] XLJKHNWPARRRJB-UHFFFAOYSA-N 0.000 claims description 10
- 238000001354 calcination Methods 0.000 claims description 9
- 230000004044 response Effects 0.000 claims description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 8
- 238000000227 grinding Methods 0.000 claims description 8
- 238000005406 washing Methods 0.000 claims description 8
- 150000001868 cobalt Chemical class 0.000 claims description 7
- 239000012295 chemical reaction liquid Substances 0.000 claims description 4
- 239000002002 slurry Substances 0.000 claims description 4
- 230000008859 change Effects 0.000 claims description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 2
- 239000007795 chemical reaction product Substances 0.000 claims description 2
- 238000004140 cleaning Methods 0.000 claims description 2
- 239000012265 solid product Substances 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 abstract description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 3
- 239000001301 oxygen Substances 0.000 abstract description 3
- 229910052760 oxygen Inorganic materials 0.000 abstract description 3
- 239000004094 surface-active agent Substances 0.000 abstract description 3
- 239000000243 solution Substances 0.000 description 30
- 230000000052 comparative effect Effects 0.000 description 22
- 239000000843 powder Substances 0.000 description 19
- 239000002244 precipitate Substances 0.000 description 12
- 238000005303 weighing Methods 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- QGUAJWGNOXCYJF-UHFFFAOYSA-N cobalt dinitrate hexahydrate Chemical compound O.O.O.O.O.O.[Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O QGUAJWGNOXCYJF-UHFFFAOYSA-N 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 6
- 229910021641 deionized water Inorganic materials 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 239000004570 mortar (masonry) Substances 0.000 description 6
- -1 polytetrafluoroethylene Polymers 0.000 description 6
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 6
- 239000004810 polytetrafluoroethylene Substances 0.000 description 6
- 238000001291 vacuum drying Methods 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 238000001878 scanning electron micrograph Methods 0.000 description 5
- 238000012546 transfer Methods 0.000 description 5
- 229910017052 cobalt Inorganic materials 0.000 description 4
- 239000010941 cobalt Substances 0.000 description 4
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- GFHNAMRJFCEERV-UHFFFAOYSA-L cobalt chloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].[Cl-].[Co+2] GFHNAMRJFCEERV-UHFFFAOYSA-L 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000002341 toxic gas Substances 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000009360 aquaculture Methods 0.000 description 1
- 244000144974 aquaculture Species 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
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- 230000002349 favourable effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
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- 238000009776 industrial production Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
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- 231100000331 toxic Toxicity 0.000 description 1
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- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G15/00—Compounds of gallium, indium or thallium
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
- G01N27/126—Composition of the body, e.g. the composition of its sensitive layer comprising organic polymers
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
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Abstract
The invention discloses an indium oxide nano material and application thereof. The product prepared by the invention has a porous structure and a larger specific surface area, can effectively adsorb more oxygen and target gas, and improves the sensing performance; the method disclosed by the invention completely does not use a surfactant, is low in cost and simple in preparation method, has excellent gas-sensitive performance on the hydrogen sulfide gas, and has an application prospect in the aspect of detection of the hydrogen sulfide gas.
Description
Technical Field
The invention relates to the technical field of nano materials, in particular to an indium oxide nano material and application thereof.
Background
Hydrogen sulfide (H) 2 S) is a by-product of different industries, such as oil refining, sewage systems, aquaculture and natural gas production, a colorless toxic gas, with a rotten or malodorous smell, one of the most harmful gases, which can have various effects on the environment and human health. The research and development of high-performance gas sensors are of great significance no matter in the detection of environmental pollution gases or the protection of human safety. With the attention on environmental protection and the strict monitoring on the emission of toxic and harmful gases, gas detection and early warning devices come into existence, and further get industryCommercialization and commercialization. The semiconductor gas sensor has the characteristics of high detection sensitivity, quick response recovery, low price and the like, and is widely applied to the field of various gas detection.
Indium oxide is a typical n-type semiconductor, is white or yellowish powder at normal temperature, is converted into reddish brown at high temperature, is insoluble in water, is soluble in hot inorganic acid, and has a melting point of 2000 ℃. Because indium oxide has small resistivity, wide forbidden band width, high catalytic activity and excellent photoelectric property, the indium oxide is widely applied to a plurality of fields such as gas sensors, photoelectric fields, solar cells, field emission and the like. The main factor affecting the performance of the indium oxide nano material is the structural morphology, so currently, many researchers are dedicated to research on controlling the generation of the indium oxide material morphology so as to improve the performance of various aspects of the indium oxide nano material. However, in the process of preparing an indium oxide material, there are many reasons that the morphology of the indium oxide material can be affected, and the research on the indium oxide material, especially the nano-scale structural morphology of the indium oxide material, in the prior art is in the beginning stage, in order to obtain different material morphologies, the preparation method is often subjected to severe requirements, such as the defects of complex operation, high production cost and the like of the preparation method, so that the research result is difficult to be put into practical industrial production in a large range.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide an indium oxide nano material to solve the problems that the indium oxide nano material prepared by the prior art is small in specific surface area, high in production cost and difficult to industrially apply.
In order to solve the technical problems, the invention adopts the following technical scheme:
an indium oxide nano material is prepared by the following method:
step 1: adding DMF into a container, adding cobalt salt and terephthalic acid, and uniformly stirring;
step 2: adding DMF, indium nitrate tetrahydrate and terephthalic acid into another container, and uniformly stirring;
and step 3: adding the solution obtained in the step (1) into the solution obtained in the step (2), and uniformly stirring to obtain a reaction solution; wherein, in the reaction liquid, the molar concentration ratio of cobalt ions, indium nitrate tetrahydrate and terephthalic acid is 1: (1-5): (2-6);
and 4, step 4: transferring the reaction liquid obtained in the step (3) into a reaction kettle, heating to 120-180 ℃, preserving heat for 2-6 hours, and cooling to room temperature;
and 5: cleaning and centrifugally separating the reaction product obtained in the step (4), and drying the solid product after washing;
and 6: and (5) grinding the dried sample in the step (5), dispersing and placing the sample in a crucible, placing the crucible in a tube furnace for calcining, heating the sample to 350-500 ℃ within 3-8 h, keeping the temperature for 1-3 h at a heating rate of not more than 5 ℃/min, and cooling the sample to room temperature to obtain the light yellow indium oxide nano material.
The invention also provides an application of the indium oxide nano material, and the indium oxide nano material is used as a gas-sensitive material for detecting hydrogen sulfide gas.
Compared with the prior art, the invention has the following beneficial effects:
1. the method comprises the steps of taking indium nitrate tetrahydrate, cobalt salt and terephthalic acid as raw materials, taking DMF as a solvent, and combining solvothermal reaction with calcination treatment to obtain indium oxide with a hexagonal box shape; the indium oxide material with the morphology has a large specific surface area, can effectively adsorb more gases, and the prepared sensor has excellent sensitivity to hydrogen sulfide, so that the sensing performance is improved.
2. The method disclosed by the invention completely does not use a surfactant, is low in raw material cost, can change the shape of the indium oxide through the cobalt salt, and is simple in material preparation operation.
3. The indium oxide nano material synthesized by the method has extremely high sensitivity to hydrogen sulfide gas, and can distinguish hydrogen sulfide from other toxic gases.
Drawings
FIG. 1 is an SEM image of hexagonal-prism-shaped indium oxide nanomaterial prepared in example 1.
Fig. 2 is an SEM image of the hexagonal prism indium oxide material prepared in comparative example 1.
Fig. 3 is an XRD pattern of indium oxide prepared in example 1 and comparative example 1.
Fig. 4 is an XPS chart of indium oxides prepared in example 1 and comparative example 1.
FIG. 5 shows XPS fine spectra of cobalt element of indium oxides obtained in example 1 and comparative example 1.
FIG. 6 is an SEM image of hexagonal-prism-shaped indium oxide nanomaterials prepared in example 4.
Fig. 7 is a graph showing hydrogen sulfide gas-sensitive responses of the hexagonal-prism-shaped indium oxide sensor device of example 1 and the hexagonal-prism-shaped indium oxide sensor device of comparative example 1 at different temperatures.
Fig. 8 is a graph of the response of the hexagonal-prism indium oxide sensing device of example 1 and the hexagonal-prism indium oxide sensing device of comparative example 1 to 2ppm of hydrogen sulfide gas.
Fig. 9 is a bar graph of the response of the hexagonal-prism indium oxide sensing device of example 1 and the hexagonal-prism indium oxide sensing device of comparative example 1 to 100ppm different gases.
Detailed Description
The invention will be further explained with reference to the drawings and examples.
First, an embodiment
Example 1: an indium oxide nano material is prepared by the following method:
(1) taking 15 mL of DMF by a pipettor, putting the DMF into a clean and dry 100mL beaker (No. 1), putting a clean magnetic rotor, accurately weighing 0.2mmol of cobalt nitrate hexahydrate and 0.2mmol of terephthalic acid by using an electronic analytical balance, adding the mixture into the beaker (No. 1), and putting the beaker on a magnetic stirrer to stir for 30 min;
(2) taking 15 mL of DMF by a pipettor, putting the DMF into a clean and dry 100mL beaker (No. 2), putting a clean magnetic rotor, accurately weighing 0.6mmol of indium nitrate tetrahydrate and 0.6mmol of terephthalic acid by using an electronic analytical balance, adding the indium nitrate tetrahydrate and the terephthalic acid into the beaker (No. 2), and putting the beaker on a magnetic stirrer to stir for 30 min;
(3) taking the solution in the beaker (No. 1) by using a liquid transfer gun, adding the solution into the beaker (No. 2), and stirring for 6 hours on a magnetic stirrer;
(4) transferring the solution to a polytetrafluoroethylene lining, placing the lining into a reaction kettle, placing the reaction kettle into an oven under the condition of 160 ℃, keeping the temperature for 4 hours after the temperature is raised to 160 ℃, and naturally cooling to room temperature.
(5) And transferring the precipitate to a centrifugal tube, washing the precipitate with deionized water and absolute ethyl alcohol respectively for three times by using a centrifugal machine to obtain powder, putting the powder into a vacuum drying oven for drying, heating to 60 ℃, and keeping the temperature for 12 hours.
(6) And grinding the dried sample uniformly in a mortar, dispersing the ground sample in a crucible, putting the crucible into a tube furnace for calcination, heating the sample to 400 ℃ for 3 hours, preserving the heat for 2 hours, and naturally cooling the sample to room temperature to obtain a light yellow powder sample.
Example 2: an indium oxide nano material is prepared by the following method:
(1) taking 15 mL of DMF by a pipettor, putting the DMF into a clean and dry 100mL beaker (No. 1), putting a clean magnetic rotor, accurately weighing 0.4mmol of cobalt nitrate hexahydrate and 0.4mmol of terephthalic acid by using an electronic analytical balance, adding the mixture into the beaker (No. 1), and putting the beaker on a magnetic stirrer to stir for 30 min;
(2) taking 15 mL of DMF by a pipettor, putting the DMF into a clean and dry 100mL beaker (No. 2), putting a clean magnetic rotor, accurately weighing 0.4mmol of indium nitrate tetrahydrate and 0.4mmol of terephthalic acid by using an electronic analytical balance, adding the indium nitrate tetrahydrate and the terephthalic acid into the beaker (No. 2), and putting the beaker on a magnetic stirrer to stir for 30 min;
(3) taking the solution in the beaker (No. 1) by using a liquid transfer gun, adding the solution into the beaker (No. 2), and stirring for 6 hours on a magnetic stirrer;
(4) transferring the solution to a polytetrafluoroethylene lining, placing the lining into a reaction kettle, placing the reaction kettle into an oven under the condition of 160 ℃, keeping the temperature for 4 hours after the temperature is raised to 160 ℃, and naturally cooling to room temperature.
(5) And transferring the precipitate to a centrifugal tube, washing the precipitate with deionized water and absolute ethyl alcohol respectively for three times by using a centrifugal machine to obtain powder, putting the powder into a vacuum drying oven for drying, heating to 60 ℃, and keeping the temperature for 12 hours.
(6) And grinding the dried sample uniformly in a mortar, dispersing the ground sample in a crucible, putting the crucible into a tube furnace for calcination, heating the sample to 400 ℃ for 3h, preserving the heat for 2h, and naturally cooling the sample to room temperature to obtain a light yellow powder sample.
Example 3: an indium oxide nano material is prepared by the following method:
(1) taking 15 mL of DMF by a pipettor, putting the DMF into a clean and dry 100mL beaker (No. 1), putting a clean magnetic rotor, accurately weighing 0.2mmol of cobalt nitrate hexahydrate and 0.2mmol of terephthalic acid by using an electronic analytical balance, adding the mixture into the beaker (No. 1), and putting the beaker on a magnetic stirrer to stir for 30 min;
(2) taking 15 mL of DMF by a pipettor, putting the DMF into a clean and dry 100mL beaker (No. 2), putting a clean magnetic rotor, accurately weighing 0.6mmol of indium nitrate tetrahydrate and 0.6mmol of terephthalic acid by using an electronic analytical balance, adding the indium nitrate tetrahydrate and the terephthalic acid into the beaker (No. 2), and putting the beaker on a magnetic stirrer to stir for 30 min;
(3) taking the solution in the beaker (No. 1) by a pipette, adding the solution into the beaker (No. 2), stirring for 3 hours on a magnetic stirrer,
(4) transferring the solution to a polytetrafluoroethylene lining, placing the lining into a reaction kettle, placing the reaction kettle into an oven under the condition of 160 ℃, keeping the temperature for 4 hours after the temperature is raised to 160 ℃, and naturally cooling to room temperature.
(5) And transferring the precipitate to a centrifugal tube, washing the precipitate with deionized water and absolute ethyl alcohol respectively for three times by using a centrifugal machine to obtain powder, putting the powder into a vacuum drying oven for drying, heating to 60 ℃, and keeping the temperature for 12 hours.
(6) And grinding the dried sample uniformly in a mortar, dispersing the ground sample in a crucible, putting the crucible into a tube furnace for calcination, heating the sample to 400 ℃ for 3 hours, preserving the heat for 2 hours, and naturally cooling the sample to room temperature to obtain a light yellow powder sample.
Example 4: an indium oxide nano material is prepared by the following method:
(1) taking 15 mL of DMF by a pipettor, putting the DMF into a clean and dry 100mL beaker (No. 1), putting a clean magnetic rotor, accurately weighing 0.2mmol of cobalt chloride hexahydrate and 0.2mmol of terephthalic acid by using an electronic analytical balance, adding the mixture into the beaker (No. 1), and putting the beaker on a magnetic stirrer to stir for 30 min;
(2) taking 15 mL of DMF by a pipettor, putting the DMF into a clean and dry 100mL beaker (No. 2), putting a clean magnetic rotor, accurately weighing 0.6mmol of indium nitrate tetrahydrate and 0.6mmol of terephthalic acid by using an electronic analytical balance, adding the indium nitrate tetrahydrate and the terephthalic acid into the beaker (No. 2), and putting the beaker on a magnetic stirrer to stir for 30 min;
(3) taking the solution in the beaker (No. 1) by a pipette, adding the solution into the beaker (No. 2), stirring for 6 hours on a magnetic stirrer,
(4) transferring the solution to a polytetrafluoroethylene lining, placing the lining into a reaction kettle, placing the reaction kettle into an oven under the condition of 160 ℃, keeping the temperature for 4 hours after the temperature is raised to 160 ℃, and naturally cooling to room temperature.
(5) And transferring the precipitate to a centrifugal tube, washing the precipitate with deionized water and absolute ethyl alcohol respectively for three times by using a centrifugal machine to obtain powder, putting the powder into a vacuum drying oven for drying, heating to 60 ℃, and keeping the temperature for 12 hours.
(6) And grinding the dried sample uniformly in a mortar, dispersing the ground sample in a crucible, putting the crucible into a tube furnace for calcination, heating the sample to 400 ℃ for 3h, preserving the heat for 2h, and naturally cooling the sample to room temperature to obtain a light yellow powder sample.
Comparative example 1:
(1) a clean and dry 100mL beaker containing 30 mL of DMF was placed in a pipette and accurately weighed with an electronic analytical balance to give 0.8mmol of indium nitrate tetrahydrate and 0.8mmol of terephthalic acid, which was then placed on a magnetic stirrer and stirred for 6 hours.
(2) Transferring the solution to a polytetrafluoroethylene lining, placing the lining into a reaction kettle, placing the reaction kettle into an oven under the condition of 160 ℃, keeping the temperature for 4 hours after the temperature is raised to 160 ℃, and naturally cooling to room temperature.
(3) And transferring the precipitate to a centrifugal tube, washing the precipitate with deionized water and absolute ethyl alcohol respectively for three times by using a centrifugal machine to obtain powder, putting the powder into a vacuum drying oven for drying, heating to 60 ℃, and keeping the temperature for 12 hours.
(4) And grinding the dried sample uniformly in a mortar, dispersing the ground sample in a crucible, putting the crucible into a tube furnace for calcination, heating the sample to 400 ℃ for 3h, preserving the heat for 2h, and naturally cooling the sample to room temperature to obtain a light yellow powder sample.
Comparative example 2:
(1) taking 15 mL of DMF by a pipettor, putting the DMF into a clean and dry 100mL beaker (No. 1), putting a clean magnetic rotor, accurately weighing 0.2mmol of cobalt nitrate hexahydrate and 0.2mmol of terephthalic acid by using an electronic analytical balance, adding the mixture into the beaker (No. 1), and putting the beaker on a magnetic stirrer to stir for 30 min;
(2) taking 15 mL of DMF by a liquid transfer machine, putting the DMF into a clean and dry 100mL beaker (No. 2), accurately weighing 0.6mmol of indium nitrate tetrahydrate and 0.6mmol of terephthalic acid by an electronic analytical balance, adding the mixture into the beaker (No. 2), putting the beaker on a magnetic stirrer, and stirring for 30 min;
(3) taking the solution in the beaker (No. 1) by using a liquid transfer gun, adding the solution into the beaker (No. 2), and stirring the solution on a magnetic stirrer for 30 min;
(4) transferring the solution to a polytetrafluoroethylene lining, placing the lining into a reaction kettle, placing the reaction kettle into an oven under the condition of 160 ℃, keeping the temperature for 4 hours after the temperature is raised to 160 ℃, and naturally cooling to room temperature.
(5) And transferring the precipitate to a centrifugal tube, washing the precipitate with deionized water and absolute ethyl alcohol respectively for three times by using a centrifugal machine to obtain powder, putting the powder into a vacuum drying oven for drying, heating to 60 ℃, and keeping the temperature for 12 hours.
(6) And grinding the dried sample uniformly in a mortar, dispersing the ground sample in a crucible, putting the crucible into a tube furnace for calcination, heating the sample to 400 ℃ for 3h, preserving the heat for 2h, and naturally cooling the sample to room temperature to obtain a light yellow powder sample.
Comparative example 2 in the step (3), the mixed solution was stirred on a magnetic stirrer for 30min, at which time the color of the reaction solution after stirring was pink clear solution, while the color of the reaction solution after stirring in example 1 was gray black, because the reaction in the reaction solution did not proceed sufficiently due to insufficient stirring time in comparative example 2, the obtained product was very little, and the product yield was very low. After extensive studies on the reaction, it was found that the length of stirring time affected the yield of the final product, and if the stirring time was less than 30min, the yield of the product was less than one fifth of the yield of the product of example 1. Therefore, in step (3), the stirring time should be not less than 30 min.
Second, the performance analysis of the examples and comparative examples
FIG. 1 is an SEM image of hexagonal indium oxide nano-material obtained by the present invention (example 1), which is box-shaped; as shown in FIG. 1, the indium oxide nano material of the invention has a hexagonal box shape, a diameter of 1-2 μm, a length of 1-2 μm, and a porous structure with a large specific Surface Area (BET Surface Area =57.38 m) 2 g -1 ) And gas attachment sites are increased, so that gas-sensitive reaction is facilitated. Meanwhile, through intensive research, the invention discovers that not only cobalt nitrate hexahydrate can influence the appearance of indium oxide, but also the appearance of the product indium oxide is changed similarly when other cobalt salts are used for preparing indium oxide, such as cobalt chloride hexahydrate used in example 4, and supposing that cobalt salts containing cobalt ions can generate favorable influence on the appearance of indium oxide, and this point can be seen from comparative example 1, the appearance of indium oxide obtained without cobalt ions participating in is obviously different from the appearance of indium oxide obtained with cobalt ions participating in, so that the appearance of indium oxide can be favorably influenced by adding cobalt salts in the process of preparing indium oxide.
FIG. 2 is a SEM image of a hexagonal prism-shaped indium oxide material obtained in comparative example 1 without cobalt ions, and shows a hexagonal rod shape, a diameter of 1-2 μm, a length of 10-30 μm, a larger length and a larger specific Surface Area (BET Surface Area =32.73 m) than those of example 1 2 g -1 ) Smaller, not conducive to gas sensitive reaction. As can be seen from the comparison between fig. 1 and fig. 2, the existence of cobalt ions in the solution has a very significant effect on the morphology of indium oxide, and the effect is very beneficial and positive, so that indium oxide originally having a hexagonal rod-like structure is changed to form a hexagonal box morphology, the specific surface area of indium oxide is increased, and the gas attachment sites are increased; on the other hand, when the solution reacts, the existence of cobalt ions increases the number of oxygen vacancies in the hexagonal-prism-shaped indium oxide nanometer material, and both aspects are beneficial to the gas-sensitive reaction.
Fig. 3, 4 and 5 show XRD, XPS full spectrum and XPS fine spectrum of cobalt element of the materials obtained in example 1 and comparative example 1, and it can be seen that indium oxide is present in the materials obtained in comparative example 1 and example 1, but cobalt element is present in the indium oxide obtained in example 1. Fig. 6 is an SEM morphology of the indium oxide material obtained in example 4, which shows a box shape, and cobalt chloride hexahydrate is synthesized instead of cobalt nitrate hexahydrate, which illustrates that the morphology of indium oxide can be changed by other cobalt sources, and that hexagonal rod-shaped indium oxide can be shortened to a box-shaped indium oxide nano material.
Therefore, the indium oxide nano material has a hexagonal box shape, and the porous structure has a large specific Surface Area (BET Surface Area =57.38 m) 2 g -1 ) In the presence of cobalt ions, oxygen vacancies of the obtained hexagonal box indium oxide nano material are increased, and the gas-sensitive performance is further enhanced; and the preparation method does not use a surfactant, and has the characteristics of low cost, simple preparation method and the like.
Third, the application of the indium oxide nano material of the invention
The hexagonal-prism-box indium oxide nano material prepared by the preparation method of the indium oxide nano material can be used for detecting hydrogen sulfide. And depositing the obtained hexagonal box indium oxide nano material on the surface of the electrode to obtain a sensing device, and detecting the hydrogen sulfide through the change of the resistance before and after the sensor is contacted with the hydrogen sulfide gas, wherein the sensitivity of the gas sensor is defined as Ra/Rg (Ra is the resistance in the air, and Rg is the resistance in the target hydrogen sulfide gas). And dispersing the prepared indium oxide material in absolute ethyl alcohol, dropwise adding the uniformly dispersed material thick slurry on an electrode by using a liquid transfer gun, and aging for 24 hours in a vacuum environment to obtain the gas sensor.
The gas sensors prepared by the method of the embodiment 1 and the comparative example 1, and the hexagonal-prism-shaped indium oxide nano material (Co-In) prepared by the embodiment 1 2 O 3 ) Sensor and hexagonal prism indium oxide material (In) In comparative example 1 2 O 3 ) And (3) carrying out performance test comparison on the sensor:
FIG. 7 shows that the optimum operating temperature for the devices prepared in example 1 and comparative example 1 is 225 deg.C;
FIG. 8 is a graph of the gas-sensitive response of the devices prepared in example 1 and comparative example 1 to 2ppm of hydrogen sulfide gas at 225 deg.C, the results indicating that the device prepared in example 1 has a better gas-sensitive response than the device prepared in comparative example 1;
fig. 9 is a bar graph of the gas response of the devices prepared in example 1 and comparative example 1 at 225 c, tested against 100ppm of different gases, showing that example 1 has an extremely high response to hydrogen sulfide, effectively distinguishing it from other gases.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the technical solutions, and those skilled in the art should understand that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all that should be covered by the claims of the present invention.
Claims (9)
1. An indium oxide nano material is characterized by being prepared by the following method:
step 1: adding DMF into a container, adding cobalt salt and terephthalic acid, and uniformly stirring;
step 2: adding DMF, indium nitrate tetrahydrate and terephthalic acid into another container, and uniformly stirring;
and step 3: adding the solution obtained in the step (1) into the solution obtained in the step (2), and uniformly stirring to obtain a reaction solution; wherein, in the reaction liquid, the molar concentration ratio of cobalt ions, indium nitrate tetrahydrate and terephthalic acid is 1: (1-5): (2-6);
and 4, step 4: transferring the reaction liquid obtained in the step (3) into a reaction kettle, heating to 120-180 ℃, preserving heat for 2-6 hours, and cooling to room temperature;
and 5: cleaning and centrifugally separating the reaction product obtained in the step (4), and drying the solid product after washing;
step 6: and (5) grinding the dried sample in the step (5), dispersing and placing the sample in a crucible, placing the crucible in a tube furnace for calcining, heating the sample to 350-500 ℃ within 3-8 h, keeping the temperature for 1-3 h at a heating rate of not more than 5 ℃/min, and cooling the sample to room temperature to obtain the light yellow indium oxide nano material.
2. The indium oxide nanomaterial according to claim 1, wherein in step 3, the stirring time is not less than 30 min.
3. The indium oxide nanomaterial according to claim 1, wherein in step 3, the molar concentration ratio of cobalt ions, indium nitrate tetrahydrate, and terephthalic acid is 1: (2-4): (3-5).
4. The indium oxide nanomaterial according to claim 1, wherein in step 4, the reaction temperature is 150 ℃ to 170 ℃.
5. The indium oxide nanomaterial according to claim 1, wherein the holding time in step 4 is 3 to 5 hours.
6. The indium oxide nanomaterial according to claim 1, wherein in step 6, the temperature is raised to 400-450 ℃ within 3-4 h, the temperature raising rate is not more than 3 ℃/min, and the temperature is maintained for 1-2 h.
7. An application of the indium oxide nano material is characterized in that the indium oxide nano material as claimed in any one of claims 1 to 6 is used as a gas-sensitive material for detecting hydrogen sulfide gas.
8. The application of the indium oxide nanomaterial of claim 7, wherein the indium oxide nanomaterial of any one of claims 1 to 6 is dissolved in absolute ethyl alcohol to prepare a solution with a concentration of 25g/L, the solution is uniformly dispersed to form a thick slurry, the thick slurry is dripped on the surface of the interdigital electrode, and the thick slurry is aged in a vacuum environment for 24 hours to obtain the hydrogen sulfide gas detection gas sensitive device.
9. The use of indium oxide nanomaterial according to claim 8, wherein the indium oxide nanosensor detects hydrogen sulfide gas comprising the steps of:
(1) obtaining the stable resistance value R of the indium oxide sensing device in dry space a ；
(2) Introducing hydrogen sulfide to enable the hydrogen sulfide to act on the indium oxide sensing device;
(3) stable resistance value R of indium oxide sensing device under action of hydrogen sulfide g ；
(4) Calculating the response value of the indium oxide sensing device according to the relative change of the resistance, wherein the calculation formula is as follows: r a /R g Wherein R is a And R g Respectively, the stable resistance values of the sensing device under the action of dry air and hydrogen sulfide.
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