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Hydrogen selective gas sensitive element

A gas sensor, selective technology, applied in measuring devices, material analysis through electromagnetic means, instruments, etc., can solve problems such as interference, false alarms, low hydrogen sensitivity, etc., and achieve a specific effect

Inactive Publication Date: 2014-09-24
WUHAN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, most gas alarms at home and abroad are the first choice for semiconductor gas sensors, which are based on metal oxide semiconductors such as SnO 2 , ZnO, WO 3 etc. are sensitive materials, due to the gas-sensitive broad-spectrum characteristics of metal oxide semiconductors and the low sensitivity to hydrogen, false alarms and interference caused by other gases often occur

Method used

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  • Hydrogen selective gas sensitive element

Examples

Experimental program
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Effect test

Embodiment 1

[0029] Production process of hydrogen selective gas sensor:

[0030] (1) Coat the outer surface of the aluminum metal tube (3-4cm in length, 6-8mm in outer diameter, and 1.5mm in wall thickness) and the inner surface of both ends of the tube (within 1cm from the mouth of the tube) with polyacrylic resin for protection, in 0.2M sulfuric acid Under the condition of constant pressure in the solution, the inner surface is anodized twice to prepare the inner anodized porous aluminum oxide (AAO) membrane tube, then the polyacrylic acid protective film is washed away with acetone, and the aluminum support at both ends of the AAO membrane tube is coated with paraffin tube (to avoid its damage during pickling), in 0.2M CuCl 2 and 0.2M hydrochloric acid to remove the unreacted metal aluminum on the surface, soak in the chromic acid and phosphoric acid mixture for 10 minutes to remove the aluminum oxide barrier layer on the outer surface, and finally obtain a tubular AAO film with a thro...

Embodiment 2

[0035] Production process of hydrogen selective gas sensor:

[0036] (1) Coat the outer surface of the aluminum metal tube (3-4cm in length, 6-8mm in outer diameter, and 1.5mm in wall thickness) and the inner surface of both ends of the tube (within 1cm from the mouth of the tube) with polyacrylic resin for protection, in 0.1M sulfuric acid Under the condition of constant pressure in the solution, the inner surface is anodized twice to prepare the inner anodized porous aluminum oxide (AAO) membrane tube, then the polyacrylic acid protective film is washed away with acetone, and the aluminum support at both ends of the AAO membrane tube is coated with paraffin tube (to avoid its damage during pickling), in 0.1M CuCl 2 and 0.1M hydrochloric acid to remove the unreacted metal aluminum on the surface, soak in the mixed solution of chromic acid and phosphoric acid for 15 minutes to remove the aluminum oxide barrier layer on the outer surface, and finally obtain a tubular AAO film w...

Embodiment 3

[0041] Production process of hydrogen selective gas sensor:

[0042] (1) Coat the outer surface of the aluminum metal tube (length 4-5cm, outer diameter 6-8mm, wall thickness 2mm) and the inner surface of both ends of the tube (within 1cm from the mouth of the tube) with polyacrylic resin for protection, in 0.1M sulfuric acid solution The inner surface is anodized twice under the condition of medium constant pressure to prepare the inner anodized porous aluminum oxide (AAO) membrane tube, then the polyacrylic acid protective film is washed away with acetone, and the aluminum support tube at both ends of the AAO membrane tube is coated with paraffin (to avoid its destruction during the pickling process), in 0.2M CuCl 2 and 0.2M hydrochloric acid to remove the unreacted metal aluminum on the surface, soak in the mixed solution of chromic acid and phosphoric acid for 15 minutes to remove the aluminum oxide barrier layer on the outer surface, and finally obtain a tubular AAO film ...

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Abstract

The invention discloses a hydrogen selective gas sensitive element. A porous anodic alumina film tube is adopted as a gas filtration film. The two ends of the porous anodic alumina film tube are provided with aluminum supporting tubes. A heating metal wire penetrates through a ceramic tube to be embedded into the aluminum supporting tubes and is connected with a heating electrode and communicated with the exterior. The outer surface of the ceramic tube is coated with metallic oxide gas sensitive materials. The gas sensitive materials are connected with a measuring electrode and communicated with the exterior. The aperture of the porous anodic alumina film tube is smaller than 0.5 nm. The gas sensitive materials are platinum doped stannic oxide nanometer materials. The average grain diameter of the gas sensitive materials ranges from 5 nm to 10 nm. The platinum doping amount accounts for 0.5% to 5% of the gas sensitive materials by weight. According to the hydrogen selective gas sensitive element, the porous anodic alumina film with the molecular sieving effect and the aperture being smaller than 0.5 nm is used for separating environment gases, the other combustible gases except hydrogen cannot pass through the porous anodic alumina film, metallic oxide gas sensitive materials located inside the alumina film tube can conduct a gas sensitive reaction only on the hydrogen entering the film tube, and therefore the hydrogen selective gas sensitive element is fast and accurate and has specificity.

Description

technical field [0001] The invention belongs to the technical field of metal oxide semiconductor gas sensor, in particular to a selective hydrogen gas sensor. Background technique [0002] Hydrogen is an important industrial gas, widely used in petrochemical industry, electronics industry, metallurgical industry, food processing, float glass, fine organic synthesis, aerospace, etc., and it is also an ideal secondary energy source. Hydrogen is colorless, tasteless, odorless, and flammable. When the content in air is 4% to 74% (volume), it will form an explosive gas mixture. Hydrogen gas leakage is very dangerous. Hydrogen alarms and hydrogen detectors should be installed in places where hydrogen is stored and used. At present, most gas alarms at home and abroad are the first choice for semiconductor gas sensors, which are based on metal oxide semiconductors such as SnO 2 , ZnO, WO 3 etc. are sensitive materials, due to the wide-spectrum gas-sensing characteristics of metal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/407
Inventor 林志东洪玉元王学华李娜
Owner WUHAN INSTITUTE OF TECHNOLOGY