Preparation method of noble metal doped In2O3/SnO3 porous-channel structured gas-sensitive material

A technology of gas-sensitive materials and precious metals, which is applied in the field of ceramic material synthesis, can solve the problems of difficult detection of gas types and difficult materials, and achieve the effects of improving gas sensitivity, simple raw material preparation, and high sensitivity

Inactive Publication Date: 2011-02-16
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the porous microstructure plays an important role in improving the gas sensitivity of gas-sensitive materials, the same metal oxide is not only sensitive to one gas under certain temperature conditions, but may be sensitive to several gases, which leads people to be sensitive to gas types. The difficulty of detection requires further improvement of the selectivity of gas-sensitive materials, so that the prepared sensor is only sensitive to the detected gas during use; the realization of this goal is difficult with only one metal oxide material, Therefore, gas-sensing material researchers proposed to use composite metal oxides to improve the selectivity of gas-sensing materials.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Will be commercially available In 2 o 3 , SnO 2 powder and Ag powder (In 2 o 3 and SnO 2 0.05% of the total amount), the powder particle size is between 50-500nm, the purity reaches 99.995%, and it is loaded into a steel mold (In 2 o 3 :SnO 2 =4:1), according to the conditions of pressing pressure of 90MPa and holding pressure for 3 minutes, the green body was pressed into a green body, and then the green body was put into a self-made sintering furnace for in-situ sintering growth. Raise to 600°C, hold for 1 hour, then raise the temperature to 1300°C, hold for 5 hours, and finally cool down with the furnace. During the heating process, the oxygen flow rate is maintained at 8L / min. The purity of oxygen is required to be higher than 99.999%, and the dew point is lower than -72°C.

Embodiment 2

[0018] Will be commercially available In 2 o 3 , SnO 2 powder and Pt powder (In 2 o 3 and SnO 2 0.05% of the total amount), the powder particle size is between 50-500nm, the purity reaches 99.995%, and it is loaded into a steel mold (In 2 o 3 :SnO 2 =7:3), according to the conditions of pressing pressure of 65MPa and holding pressure for 2 minutes, the green body was pressed into a green body, and then the green body was put into a self-made sintering furnace for in-situ sintering growth. Raise to 700°C, hold for 2 hours, then raise the temperature to 1450°C, hold for 2 hours, preferably cool with the furnace, keep the oxygen flow rate at 5L / min during the heating process, the purity of oxygen should be higher than 99.999%, and the dew point should be lower than -72°C.

Embodiment 3

[0020] Will be commercially available In 2 o 3 , SnO 2 powder and Pd powder (In 2 o 3 and SnO 2 0.05% of the total amount), the powder particle size is between 50-500nm, the purity reaches 99.995%, and it is loaded into a steel mold (In 2 o 3 : SnO 2 =3:2), according to the conditions of pressing pressure of 80MPa and holding pressure for 5 minutes, the green body was pressed into a green body, and then the green body was put into a self-made sintering furnace for in-situ sintering growth. The specific sintering process was as follows: a heating rate of 80°C / h Raise to 650°C and hold for 1 hour, then raise the temperature to 1250°C and hold for 3 hours. It is best to cool with the furnace. During the heating process, the oxygen flow rate should be kept at 3L / min. The purity of oxygen should be higher than 99.999%, and the dew point should be lower than -72°C.

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Abstract

The invention relates to a preparation method of a noble metal doped porous-channel structured In2O3 / SnO3 gas-sensitive material, which comprises the following steps of: pressing market In2O3 and SnO2 in the ratio of 4:1 or 7:3 or 3:2 together with noble metal Pt or Pd or Ag powder into a blank in a steel mold; and then, loading the blank into an oxygen atmosphere sintering furnace for solid phase sintering to finally obtain the noble metal doped porous-channel structured In2O3 / SnO3 gas-sensitive material. The addition quantity of the noble metal Pt or Pd or Ag powder accounts for 0.05% of the total quantity of In2O3 and SnO2; with respect to the oxygen atmosphere sintering condition for the in-situ sintering growth, the heating rate is 50-500 DEG C / h; a heat preservation process is divided into two stages, the temperature range of the first stage is 600-700 DEG C, and the temperature range of the second stage is 1250-1450 DEG C; the time of heat preservation is 1-5h; and the oxygen flow is 3-8 L / min. The method can increase gas sensitivity by increasing the specific surface area through the porous-channel structure and increases the selectivity of the gas-sensitive material through the nanometer noble metal. The invention has the advantages of low cost, clean production and the like and is easy to control, and the raw materials are simple to prepare.

Description

technical field [0001] The invention relates to the technical field of ceramic material synthesis, in particular to In 2 o 3 / SnO 2 The invention discloses a preparation method of a porous structure gas-sensing material. Background technique [0002] With the development of science and technology, the requirements for the detection, monitoring and alarm of flammable and toxic gases are getting higher and higher, which puts forward higher requirements for the gas-sensitive materials that the detection relies on; Sensitivity, selectivity, and long-term stability, as well as reducing operating temperature and shortening response recovery time have become important directions for the development of gas-sensitive materials. [0003] At present, researchers generally believe that the methods to improve the comprehensive performance of gas-sensing materials mainly include doping metal ions (including noble metals or rare earth elements) or metal oxides, increasing the specific s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/01C04B38/00C04B35/64
Inventor 周晓龙曹建春陈敬超阮进于杰杜焰沈黎吴大平熊大民
Owner KUNMING UNIV OF SCI & TECH
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