Multilevel structure metal oxide gas sensitive material and preparation method thereof

A gas-sensitive material and oxide technology, applied in analytical materials, cobalt oxide/cobalt hydroxide, instruments, etc., can solve the problems of response value lower than 30 and high operating temperature, achieving good linear correlation, low operating temperature, The effect of high response value

Inactive Publication Date: 2018-09-28
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] Although a variety of oxides with higher specific surface areas have been prepared in the above literature, and the response value to VOCs gas has been greatly improved, there are still operating temperatures higher than 200 ° C, and the response value to 50ppm detection gas is lower than 30. Disadvantages such as detection of gases with a concentration greater than 1ppm

Method used

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  • Multilevel structure metal oxide gas sensitive material and preparation method thereof
  • Multilevel structure metal oxide gas sensitive material and preparation method thereof
  • Multilevel structure metal oxide gas sensitive material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Step A: take by weighing 2.56g (10.0mmol) Mg(NO 3 ) 2 .6H 2 O, 2.91g (10.0mmol) Co(NO 3 ) 2 .6H 2 O and 0.80g (2.5mmol) In(NO 3 ) 3 .H 2 O was dissolved in 100ml deionized water to make a mixed salt solution; weighed 6.01g (0.1mol) urea was dissolved in 100ml deionized water to make an alkaline solution; weighed 2.76g (20.0mmol) salicylic acid was dissolved in 20ml absolute ethanol A solution is prepared in the mixture; the prepared three solutions are mixed to obtain a mixed solution.

[0036] Step B: Heat the mixed solution obtained in Step A to 90° C. under mechanical stirring, and continue the reaction at this temperature. When the pH value of the solution reaches 7, stop the reaction. After cooling to room temperature, the obtained precipitate was centrifuged and washed 4 times with deionized water and 4 times with ethanol, and then the filter cake was dried at 90°C for 12 hours to obtain a hierarchical structure assembled with layered hydroxide nanosheets ...

Embodiment 2

[0040] Step A: Weigh 1.28g (5.0mmol) Mg(NO 3 ) 2 .6H 2 O, 2.91g (10.0mmol) Co(NO 3 ) 2 .6H 2 O and 1.59g (5.0mmol) In(NO 3 ) 3 .H 2 O was dissolved in 100ml deionized water to make a mixed salt solution; 12.01g (0.2mol) urea was dissolved in 100ml deionized water to make an alkaline solution; 2.76g (20.0mmol) salicylic acid was dissolved in 40ml ethylene glycol A solution is prepared in the mixture; the prepared three solutions are mixed to obtain a mixed solution.

[0041] Step B: Heat the mixed solution obtained in Step A to 100° C. under mechanical stirring, and continue the reaction at this temperature. When the pH value of the solution reaches 8, stop the reaction. After cooling to room temperature, the obtained precipitate was centrifuged and washed 6 times with deionized water and 4 times with ethanol, and then the filter cake was dried at 90°C for 12 hours to obtain a hierarchical structure assembled with layered hydroxide nanosheets Precursor.

[0042] Step ...

Embodiment 3

[0045] Step A: Weigh 2.97g (10.0mmol) Zn(NO 3 ) 2 .6H 2 O, 2.50g (10.0mmol) Cu(SO 4 ) 2 .5H 2 O and 4.04g (10.0mmol) Fe(NO 3 ) 3 .9H 2 O was dissolved in 50ml deionized water to make a mixed salt solution; 14.02g (0.1mol) of hexamethylenetetramine was dissolved in 100ml of deionized water to make an alkaline solution; 5.53g (40.0mmol) of salicylic acid was dissolved in Prepare a solution in 20ml of n-butanol; mix the prepared three solutions to obtain a mixed solution.

[0046] Step B: Heat the mixed solution obtained in Step A to 120° C. under mechanical stirring, and continue the reaction at this temperature. When the pH value of the solution reaches 9, stop the reaction. After cooling to room temperature, the obtained precipitate was centrifuged and washed 6 times with deionized water and 4 times with ethanol, and then the filter cake was dried at 90°C for 12 hours to obtain a hierarchical structure assembled with layered hydroxide nanosheets Precursor.

[0047] S...

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Abstract

The invention provides a multilevel structure metal oxide gas sensitive material and a preparation method thereof. Urea or hexamethylenetetramine is used as an alkaline source, the increase rate of the pH value of a reaction system is retarded in virtue of an organic acid as a structure-directing agent, a water and alcohol mixed solvent is used for adjusting the growth kinetics of a wafer, a multilevel structure layered hydroxide precursor assembled by nanosheets is prepared, a multilevel structure complex oxide assembled by the nanosheets is obtained through roasting, then porous nanosheets are obtained by etching MgO or ZnO in the complex oxide through ammonium salt, more surface defects are formed, and the porous multilevel structure metal oxide gas sensitive material with low operationtemperature, high response value and low detection limit is obtained. The thicknesses of the nanosheets of the material are 5 to 20 nm, the specific surface area is 80 to 180 m<2>/g, the pore diameter is concentrated to be 2 to 15 nm, the gas adsorption, diffusion and activation are promoted, and then the gas sensitive material is improved. The method provided by the invention is simple in operation, mild in condition and convenient for industrial production.

Description

[0001] Field [0002] The invention relates to the field of gas-sensing material preparation, in particular to a multi-level structure metal oxide gas-sensing material and a preparation method thereof. Background technique [0003] Volatile Organic Compounds (Volatile Organic Compounds, referred to as VOCs) are widely used in many fields of national production as excellent solvents and important chemical raw materials. However, most VOCs are toxic and have low harmful concentrations. After long-term exposure to the human body, they enter through the respiratory tract and skin tissues. In vivo can cause serious illness and even death. Therefore, online monitoring of trace VOCs gases in the environment is of great significance for production safety and improvement of life quality. At present, VOCs gas monitoring mainly uses sensors with semiconductor metal oxides as the core, such as ZnO, SnO 2 , Fe 2 o 3 、Co 3 o 4 , CuO and other oxides have realized the detection ability...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G51/04G01N33/00
CPCC01G51/04C01P2002/72C01P2004/03G01N33/0047
Inventor 唐平贵石峰李殿卿冯拥军秦帅伟
Owner BEIJING UNIV OF CHEM TECH
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