W-Sn nano composite metal oxide gas-sensing material and preparation method thereof

A technology of nano-composite and gas-sensing materials, applied in the field of binary nano-composite metal oxide gas-sensing materials and their preparation, to achieve the effects of high adsorption performance, high sensitivity and selectivity

Inactive Publication Date: 2008-05-21
BEIJING UNIV OF CHEM TECH
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Problems solved by technology

[0005] In literature [3] Sensors and Actuators B 78 (2001) 89-97, Chiorino A et al. used SnO 2 Impregnate a small amount of W for FT-IR spectrum test and found that adding WO 3 The samples increase the IR transmittance, attribute this phenomenon to the decrease of the free electron concentration and significant

Method used

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  • W-Sn nano composite metal oxide gas-sensing material and preparation method thereof

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Embodiment 1

[0023] A. Weigh 1.7529g of SnCl 4 ·5H 2O was fully dissolved in 100ml distilled water to prepare 0.05M SnCl 4 Solution, add dilute ammonia solution drop by drop under constant stirring, stop dropping when the pH value of the solution reaches 8, and obtain α-stannic acid sol precipitation, then place it for aging for 2 hours, filter, and disperse and dissolve the filtered sol in 50ml distilled water Make the concentration 0.1M.

[0024] B. Weigh 0.3154g of (NH 4 ) 6 h 2 W 12 o 40 4H 2 O was dissolved in 12.5ml of water to make a concentration of 0.1M (NH 4 ) 6 h 2 W 12 o 40 solution, and then added dropwise to the above-mentioned 50ml α-stannic acid sol solution, the pH of the solution was 7, and then added dilute HNO 3 Solution, finally make the pH value of the solution to be 6, place it at room temperature for 24 hours, centrifuge at 4200rmp, dry the separated precipitate at 70°C, and roast at 600°C for 6 hours to obtain WO 3 -SnO 2 Composite powder, the measur...

Embodiment 2

[0026] A. with embodiment 1;

[0027] B. 0.3262g of 5 (NH 4 ) 2 O·12WO 3 ·5H 2 O was dissolved in 12.5ml of distilled water, adjusted with concentrated nitric acid to make the pH value 1, then added dropwise in the above-mentioned 50ml α-stannoic acid sol solution, and finally the pH value of the solution was adjusted to 6 with dilute ammonia to make it completely precipitated, Others are the same as in Example 1, and finally the mole of Sn / W is 4:1 WO 3 -SnO 2 Composite powder. The measured average particle size of the material is about 15nm, and the specific surface area is 43.1m 2 / g.

Embodiment 3

[0029] A. with embodiment 1;

[0030] B. Add 0.8411g of (NH 4 ) 6 h 2 W 12 o 40 4H 2 O is dissolved in 33.3ml distilled water, and others are the same as in Example 1. Preparation of WO with a Sn / W molar ratio of 1.5:1 3 -SnO 2 Composite powder. The measured average particle size of the material is about 7nm, and the specific surface area is 51.1m 2 / g.

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Abstract

The invention relates to a W-Sn nanocomposite metal oxide gas sensitive material and a preparation method thereof. The composite metal oxide is a composite of WO3 and SnO2, expressed as WO3-SnO2, wherein the Sn/W molar ratio is 1-20:1, the particle size distribution is 5.0-30.0nm, and the specific surface area is 15.0-60.0m2/g . The preparation method of this composite metal oxide adopts the step-by-step precipitation method. First, α-stannic acid is precipitated with tin salt, dispersed in water at a certain concentration, and then dropped into the tungsten salt solution with the above molar ratio of Sn/W to adjust The pH value is until the precipitation is complete. After drying, the precursor is roasted at a temperature of 400°C to 1000°C to make a nanocomposite powder. The powder is made into a sensor element, which has high adsorption performance and high sensitivity for NO2, and high selectivity for reducing gases.

Description

Technical field: [0001] The invention relates to a binary nanocomposite metal oxide gas sensitive material and a preparation method thereof. Background technique: [0002] SnO 2 It is an N-type semiconductor metal oxide, which can be used as a gas-sensing material for detecting reducing gases and oxidizing gases. The currently available SnO 2 Base sensors generally have poor thermal stability, and their sensitivity and selectivity to a certain gas are not ideal, especially during the firing process of sensor production (temperature ≥ 600 ° C), due to the SnO 2 Particle growth or agglomeration greatly reduces sensitivity and selectivity. Researchers generally believe that the sensitive characteristics of gas-sensitive materials are closely related to their particle size and thermal stability. Due to their unique size effects and surface effects, nanostructure materials are very sensitive to light, electricity, temperature and gas adsorption, and can quickly It can cause ch...

Claims

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Application Information

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IPC IPC(8): C04B35/457C04B35/628
Inventor 白守礼周国君李殿卿石冰洁陈霭璠罗瑞贤
Owner BEIJING UNIV OF CHEM TECH
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