Indium oxide carbon monoxide gas sensitive material as well as preparation method and application thereof

Abstract

The invention relates to an indium oxide carbon monoxide gas-sensitive material as well as a preparation method and application thereof. The gas-sensitive material has a heterogeneous three-stage hierarchical structure, is prepared from indium oxide sheets with a hollow structure consisting of small-diameter nanorods and a high specific surface area, shows rich active crystal faces and adsorption oxygen bonds, can effectively adsorb more oxygen and carbon monoxide gas molecules, and promotes the oxygen and carbon monoxide gas molecules to generate a redox reaction with hydrogen on the surface of the material, so that the gas-sensitive material has a good application prospect. Therefore, the detection precision of the carbon monoxide gas is obviously improved. According to the preparation method, toxic materials are not used, preparation is safe, the synthesis route is simple, repeatability is good, cost is low, and a new thought is provided for efficient and environment-friendly preparation of high-performance gas sensitive sensor materials.

Description

Technical Field

[0001] The invention relates to the technical field of gas-sensitive materials, and in particular to an indium oxide carbon monoxide gas-sensitive material and a preparation method thereof. Background Art

[0002] In recent years, with the development of industrialization, industrial waste gas has gradually eroded people's health and the environment on which people depend for survival. Therefore, people pay more and more attention to the detection and control of toxic gases. After a lot of research, researchers have gradually turned their attention to metal oxides with high sensitivity and easy operation. Among the many metal oxides, indium oxide has been favored by researchers for its unique chemical and physical properties. At present, there is little research on the morphology and structure of indium oxide gas-sensitive materials. The existing indium oxide gas-sensitive materials have low specific surface area, few pores, high density, and poor gas-sensitive performance. In addition, the research on composite materials is not comprehensive and in-depth. In order to improve the performance of indium oxide gas-sensitive materials to meet practical applications. Summary of the invention

[0003] In view of the existing deficiencies, the technical problem to be solved by the present invention is to provide a heterogeneous three-level hierarchical indium oxide gas-sensitive material and a preparation method and application thereof. The gas-sensitive material has high detection sensitivity and specific surface area, and improves the accuracy of gas-sensitive detection.

[0004] The second technical problem to be solved by the present invention is to provide a gas sensitive sensor material of indium oxide with a three-level hierarchical structure.

[0005] The third technical problem to be solved by the present invention is to provide a sensor for detecting exhaust gas prepared by using the above-mentioned three-level hierarchical structure indium oxide gas sensitive sensor material.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for preparing an indium oxide carbon monoxide gas-sensitive material, which uses In(NO3)36H2O as an indium source, urea as a graded assembly agent, zinc salt as a microstructure regulator, and deionized water as a solvent, and obtains a heterogeneous tertiary structure indium oxide carbon monoxide gas-sensitive material through calcination.

[0007] The preparation method of the above-mentioned indium oxide carbon monoxide gas sensitive sensor material comprises the following specific steps: (1) Take 2.1 g of In(NO3).6H2O, dissolve it in 10 ml of deionized water and filter it. Place the filtrate in a polytetrafluoroethylene container, add 4.5 g of urea and 0.21 g of zinc nitrate hexahydrate, and stir on a magnetic stirrer until it is fully dissolved. (2) The mixture was then placed in a 90 °C oven and heated for 6 h, then cooled naturally, and the powdery precipitate was collected by centrifugation to obtain In(OH)3 nanosheets doped with zinc. (3) The obtained In(OH)3 nanosheets doped with zinc were calcined in a calcination furnace at 400°C for 5 hours to obtain porous In2O3 nanosheets doped with zinc; the indium oxide nanosheets were heterogeneous three-level hierarchical structures with a diameter of 0.2-1 μm and a specific surface area of ​​80 m 2 / g or above.

[0008] Furthermore, the diameter of the hierarchical structure of indium oxide nanosheets is 0.3-0.5 μm, and the specific surface area under the BET measurement method is 100-130 m 2 / g.

[0009] Furthermore, the diameter of the hierarchical structure of indium oxide nanosheets was 0.5 μm, and the specific surface area under the BET measurement method was 110-120 m 2 / g.

[0010] A gas sensor for detecting carbon monoxide, wherein the material of the gas sensor is the obtained heterogeneous tertiary structured indium oxide carbon monoxide gas sensor material. The manufacturing method thereof is as follows: (1) Weigh about 2 mg of In2O3 nanosheet powder, put it into a clean agate mortar and add two drops of ethylene glycol to grind it. Continue grinding until it becomes a uniform paste; (2) Apply the paste obtained by grinding evenly on the ceramic (with heating wire inside), and then place the ceramic in a constant temperature drying oven at 40°C to dry. Apply it again after drying for 24 hours. After repeating the application five times, the ceramic coated with In2O3 nanosheets is called a gas sensor; (3) The prepared gas sensor is welded to the test base, and the test base is placed in an atmosphere hood. The machine is turned on and the gas sensor is aged. The aging condition is that the gas sensor is kept at 300 °C for 20 min. Beneficial Effects

[0011] Compared with the prior art, the heterogeneous tertiary structure indium oxide carbon monoxide gas-sensitive material of the present invention and its preparation method and application have the following advantages: (1) The structure of the indium oxide carbon monoxide gas sensor material obtained by the method of the present invention is a heterogeneous three-dimensional structure, presenting a hollow structure composed of small-diameter nanorods. This feature has a larger surface area, can expose sufficient active crystal faces and adsorbed oxygen bonds, and can effectively adsorb more oxygen and carbon monoxide gas molecules to undergo redox reactions, thereby improving the accuracy of carbon monoxide gas detection. The preparation method of the present invention avoids the use of toxic materials, is safer, has a simple synthesis route, high repeatability, and low cost; its high detection accuracy has broad application prospects in detecting the content of harmful gases in microenvironments; (2) It can stably and effectively obtain diameters below 1 μm, and the specific surface area under the bet measurement method is 110-120 m 2 / g of indium oxide nanosheet hierarchical structure, improving the effective yield of carbon monoxide gas-sensitive materials with large specific surface area indium oxide structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a SEM image of the surface morphology of an embodiment of the present invention; Figure 2 It is an element analysis Mapping diagram of an embodiment of the present invention; Figure 3 This is a gas sensing performance test diagram of an embodiment of the present invention; DETAILED DESCRIPTION

[0013] The following is a further description of the implementation scheme of the present invention in conjunction with the accompanying drawings: The following examples provide detailed implementation methods and specific operating processes based on the technical solution of the present invention, but the protection scope of the present invention is not limited to the following examples. Example

[0014] The preparation method of the above-mentioned indium oxide carbon monoxide gas sensor material comprises the following specific steps: (1) Take 2.1 g of In(NO3).6H2O, dissolve it in 10 ml of deionized water and filter it. Place the filtrate in a polytetrafluoroethylene container, add 4.5 g of urea and 0.21 g of zinc nitrate hexahydrate, and stir on a magnetic stirrer until it is fully dissolved. (2) The mixture was then placed in a 90 °C oven and heated for 6 h, then cooled naturally, and the powdery precipitate was collected by centrifugation to obtain In(OH)3 nanosheets doped with zinc. (3) The obtained zinc-doped In(OH)3 nanosheets were calcined in a calcination furnace at 400°C for 5 hours, and then slowly dehydrated naturally to obtain porous In2O3 nanosheets doped with zinc; wherein the indium oxide nanosheets were heterogeneous three-level hierarchical structures with a diameter of 0.2-1 μm and a specific surface area of ​​80 m 2 / g or above.

[0015] Furthermore, the diameter of the hierarchical structure of indium oxide nanosheets is 0.3-0.5 μm, and the specific surface area under the BET measurement method is 100-130 m 2 / g.

[0016] Preferably, the diameter of the obtained hierarchical structure of indium oxide nanosheets is 0.5 μm, and the specific surface area thereof under the bet measurement method is 110-120 m 2 / g.

[0017] A gas sensor for detecting carbon monoxide, wherein the material of the gas sensor is the obtained heterogeneous tertiary structure indium oxide carbon monoxide gas sensor material. The manufacturing method thereof is: (1) Weigh about 2 mg of In2O3 nanosheet powder, put it into a clean agate mortar and grind it with two drops of ethylene glycol. Continue grinding until it becomes a uniform paste; (2) Apply the paste obtained by grinding evenly on the ceramic (with heating wire inside), and then place the ceramic in a constant temperature drying oven at 40°C to dry. Apply it again after drying for 24 hours. After repeating the application five times, the ceramic coated with In2O3 nanosheets is called a gas sensor; (3) The prepared gas sensor is welded to the test base, and the test base is placed in an atmosphere hood. The machine is turned on and the gas sensor is aged. The aging condition is that the gas sensor is kept at 300 °C for 20 min.

[0018] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, a person skilled in the art may make non-creative modifications to the present embodiment as needed, but such modifications are protected by patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing an indium oxide carbon monoxide gas sensor material, the specific steps are as follows: (1) Take 2.1 g of In(NO3).6H2O, dissolve it in 10 ml of deionized water and filter it. Place the filtrate in a polytetrafluoroethylene container, add 4.5 g of urea and 0.21 g of zinc nitrate hexahydrate, and stir on a magnetic stirrer until it is fully dissolved. (2) The mixture was then placed in a 90 °C oven and heated for 6 h, then cooled naturally, and the powdery precipitate was collected by centrifugation to obtain In(OH)3 nanosheets doped with zinc. (3) calcining the obtained zinc-doped In(OH)3 nanosheets in a calcination furnace at 400°C for 5 hours to obtain porous In2O3 nanosheets doped with zinc; In step (3), after calcination, the nanosheets are slowly and naturally dehydrated to obtain porous In2O3 nanosheets doped with zinc. The obtained indium oxide nanosheets are heterogeneous three-level hierarchical structures with a diameter of about 0.2-1 μm and a specific surface area of ​​up to 80 m 2 / g or above.

2. The preparation method according to claim 1, characterized in that: The diameter of the hierarchical structure is about 0.3-0.5 μm, and its specific surface area can reach 100-130 m 2 / g.

3. A gas sensor for detecting carbon monoxide, wherein the material of the gas sensor is the indium oxide carbon monoxide gas sensitive material as claimed in claim 1. The manufacturing method thereof is: (1) Weigh about 2 mg of In2O3 nanosheet powder, put it into a clean agate mortar and add two drops of ethylene glycol to grind it. Continue grinding until it becomes a uniform paste; (2) Apply the paste obtained by grinding evenly on the ceramic (with heating wire inside), and then place the ceramic in a constant temperature drying oven at 40°C to dry. Apply it again after drying for 24 hours. After repeating the application five times, the ceramic coated with In2O3 nanosheets is called a gas sensor; (3) The prepared gas sensor is welded to the test base, and the test base is placed in an atmosphere hood. The machine is turned on and the gas sensor is aged. The aging condition is that the gas sensor is kept at 300 °C for 20 min.

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