Tungsten trioxide nanosheet and tungsten trioxide nanosheet-doped gas sensor

A technology of gas sensor and tungsten trioxide, which is applied in the field of nanotechnology and new materials, can solve the problems of difficult synthesis, high cost, and obstacles to the preparation of tungsten trioxide nanosheets, and achieve low equipment requirements, fast response capabilities, and excellent preparation process. simple and easy effects

Inactive Publication Date: 2014-03-12
JIANGXI NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

According to reports, with H 2 W 2 o 7 As a precursor, tungsten oxide nanosheets can be prepared by wet chemical meth

Method used

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  • Tungsten trioxide nanosheet and tungsten trioxide nanosheet-doped gas sensor

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Effect test

example 1

[0022] After thoroughly mixing 20 mL of isopropanolamine and 40 mL of ethanol, add 4 g of tungstic acid (H 2 WO 4 or WO 3 ·H 2 O), figure 1 It is a schematic diagram of the layered structure of tungstic acid. At room temperature, after magnetic stirring for 120 h, the color of tungstic acid gradually changed from light yellow to milky white. After centrifugation, a white solid was obtained. After the obtained sample is washed twice with ethanol, the resulting white powder is dried under low pressure at room temperature and is tungstic acid / organic intercalation compound. figure 2 A schematic diagram of the structure of the compound. Add the white powder to 50 mL of 5 M nitric acid solution, stir magnetically for 12 hours, and centrifuge and wash with ethanol to obtain light yellow tungstic acid (WO 3 2H 2 (0) nanosheets, then place the nanosheets in an alumina crucible, heat to 500°C at a rate of 5°C / min, keep the temperature in air for 2 h, and cool to room temperatur...

example 2

[0024] Disperse 120 mg tungsten trioxide nanosheets in 1 mL of 20mM HAuCl 4 ·3H 2 In the O aqueous solution, the solution is added dropwise to the gas sensor substrate with a heater, heat-treated at 80 °C for 10 min, then the temperature is raised to 400-500 °C, kept at a constant temperature for 0.5-2 h, taken out and cooled to room temperature, that is gas sensor.

example 3

[0026] Put 120 mg of tungsten trioxide nanosheets in 1 mL of 20 mM HAuCl 4 ·3H 2 O aqueous solution, add 2 mg of polyvinylpyrrolidone (Polyvinylpyrrolidone, average molecular weight 40000), after uniform dispersion, the solution is added dropwise to the gas sensor substrate with a heater, heat treatment at 80 °C for 10 min, and then the temperature is raised to 300-500 °C, constant temperature for 0.5-2 h, take it out and cool it to room temperature, it is a gas sensor. In the sensing test of 50 ppm hydrogen sulfide gas, it was found that the traditional solid gas sensor exhibited a phenomenon of "sleeping", that is, when the sensor was exposed to a clean environment, after a period of time (ranging from hours to months) , the first time for the gas T 90 (the time required to reach 90% gas concentration) is significantly longer than the second time, with a difference of about 20 s, such as Figure 4 As shown, the gas sensor using gold-doped tungsten trioxide nanosheets show...

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Abstract

The invention relates to a tungsten trioxide nanosheet and a tungsten trioxide nanosheet-doped gas sensor. A preparation method for the tungsten trioxide nanosheet comprises the following steps of reacting a raw material tungstic acid (WO3.xH2O) with alcohol amine to obtain an alcohol amine intercalated tungstic acid layered compound, performing oxidation by using concentrated nitric acid to remove the alcohol amine, and performing heat treatment to obtain the tungsten trioxide nanosheet. According to the tungsten trioxide nanosheet and the tungsten trioxide nanosheet-doped gas sensor, a preparation process is simple and easy, and requirements on equipment are low; the tungstic acid with a micron dimension or a millimeter dimension is used as the raw material, so that the aims of realizing stable batch production and remarkably lowering the preparation cost of the tungsten trioxide nanosheet are fulfilled; tungsten trioxide nanosheet-doped gas sensor with quick response to gas such as hydrogen sulfide can be obtained by doping the tungsten trioxide nanosheet with a trace of noble metal.

Description

technical field [0001] The invention relates to a new method capable of preparing tungsten trioxide nanosheets in batches and a novel gas sensor in which a trace amount of noble metal doped tungsten trioxide nanosheets is a gas sensitive material, belonging to the field of nano science and technology and new materials. Background technique [0002] Due to their unique physical and chemical properties such as high specific surface area, quantum size effect, small size effect and macroscopic quantum tunneling effect, nanomaterials have become one of the hotspots of current research and have attracted great attention from scientists from all over the world. At the beginning of this century, western developed countries successively increased their investment in research and development of micro-nano technology. The U.S. Department of Energy, Department of Defense, Department of Health and other national departments invested as much as 1.8 billion U.S. dollars in this field in 201...

Claims

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Application Information

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IPC IPC(8): C01G41/02G01N33/00B82Y30/00B82Y40/00
Inventor 顾刚曾凡焱刘晓山
Owner JIANGXI NORMAL UNIV
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