A kind of side heating ammonia gas sensor and preparation method

Abstract

The invention discloses an indirectly-heated ammonia gas sensor which comprises a ceramic tube, a gas-sensitive element, electrodes and an electric heating wire. The gas-sensitive element is arranged on the ceramic tube, the two ends of the gas-sensitive element are provided with the electrode respectively, the electric heating wire is arranged in the ceramic tube and used for heating the ceramic tube, and the gas-sensitive element is made of a gas-sensitive material Ag-WS2 nanopowder. The manufacturing method comprises the steps that ammonium metatungstate (NH4)6H2W12O40 is selected as a raw material, PVP(K90) is taken as a polymer precursor macromolecular solution, and an ammonium metatungstate (NH4)6H2W12O40)-PVP composite fiber mat is prepared by adopting an electrostatic spinning method; the composite fiber mat is removed from aluminum foil paper and placed in a high-temperature resistance furnace to be subjected to annealing calcinations, and then a WO3 fiber is obtained; the WO3 fiber and sulfur powder are subjected to a vulcanization reaction under nitrogen protection in a tubular furnace to synthesize lamellar nano WS2, and meanwhile Ag nanoparticles are deposited to the surface of the WS2 nanosheet. Compared with a traditional method, the manufacturing method has the advantages that an operation process is simple, energy consumption is low, and the high sensitivity and selectivity on ammonia gas are achieved.

Description

technical field [0001] The invention relates to the field of semiconductor oxide gas-sensing materials, in particular to a design method of a side-heating ammonia gas sensor. Background technique [0002] Gas sensors are closely related to people's daily life and occupy an important position in the national science and technology field and national defense construction. They are used to detect a variety of toxic and harmful gases, such as ammonia, hydrogen sulfide, sulfur dioxide, etc. Gas sensors based on semiconductor metal oxides have many advantages such as high sensitivity, fast response and recovery time, simple operation and use, and low cost, but there are still unsolved problems in practical production and life applications. First, the stability is poor and there is signal drift, which makes the final measurement result not reliable and stable. Second, the lack of accurate gas selectivity, because there are often some interfering gases in actual detection, this wil...

AI Technical Summary

Problems solved by technology

Gas sensors based on semiconductor metal oxides have many advantages such as high sensitivity, fast response and recovery time, simple operation and use, and low cost, but there are still unsolved problems in actual production and life applications.

First, the stability is poor and there is signal drift, which makes the final measurement result not reliable and stable

Second, the lack of accurate gas selectivity, due to the presence of some interfering gases in actual detection, this will cause the sensor to produce an undesired response and issue false alarms, greatly limiting its scope of use

Third, the resistance fluctuation of semiconductor oxides varies greatly at working temperature, which is mainly affected by factors such as material purity, film thickness, sintering temperature, etc., which makes the resistance value of the element relatively discrete, which cannot meet the high sensitivity in certain occasions testing requirements

Traditional gas-sensing materials have large grain or pore size, resulting in small specific surface area and large film thickness, which is not conducive to the design and production of high-performance gas-sensing components

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