High gas response and selective LaFeO3-based ethanol gas sensor element and preparation method thereof

Abstract

The invention belongs to the technical field of gas sensors, and provides a high gas response and selective LaFeO3-based ethanol gas sensor element and a preparation method thereof. LaFeO3 and BaTiO3nano powder are prepared by a sol-gel method and mixed at a molar ratio of 2:1; the mixture is sintered for 2 h at 190-210 DEG C, a nano gas-sensitive material is obtained, and a side-heating ceramictube structure gas sensor element is obtained. The oxygen adsorption capability of the surface of the nano-gas sensitive material is enhanced, and the gas response and selectivity are significant improved at lower operating temperatures. The optimum operating temperature of the gas sensor element for ethanol is 128 DEG C; the gas response to 100 ppm ethanol at the optimum operating temperature is102.9, and good stability is achieved; for 100 ppm acetone, dichloromethane, n-hexane, carbon dioxide and hydrogen and the like, the gas response is 38 or below, and good selectivity is achieved; andthe gas sensor element has a very high gas response to low concentration ethanol gas.

Description

technical field [0001] The invention belongs to the technical field of gas sensors, in particular to a high gas response and selectivity LaFeO 3 Base ethanol gas sensor element and preparation method thereof, is based on LaFeO 3 Nanoparticles as the basic working substance of sensor elements, a method to improve their ethanol gas response and selectivity. Background technique [0002] With the development of modern society, people pay more and more attention to health and safety issues. Ethanol is the main component of all kinds of alcohol, and it is also a flammable gas. Excessive drinking, drunk driving and leakage of ethanol have great health and safety Therefore, a highly sensitive, highly selective, stable and reliable ethanol gas sensor is of great significance to human health and life safety. Currently, doped semiconductor oxides SnO 2 , ZnO, TiO 2 , Fe 2 o 3 , V 2 o 5 etc. are widely used in the detection of ethanol gas. The principle is to use the oxygen ads...

AI Technical Summary

Problems solved by technology

However, based on the previous research work of scientific researchers, we found that: LaFeO 3 The resistance itself is very large, which is not conducive to practical applications, and LaFeO 3 The optimal operating temperature of ethanol-based gas sensor components is still high, usually above 200 ° C, which is not conducive to the research of low-power devices; the gas response to ethanol gas is not high enough at the optimal operating temperature, especially for low concentrations The ethanol gas response needs to be improved

The current method is mainly to replace the position of trivalent La by doping divalent elements such as Ca, Sr, Ba, Pb, or replace the position of trivalent Fe by doping with elements such as Co, Mg, Ni, etc., to provide more holes. Carriers, thereby reducing the resistance of the material and improving its gas-sensing performance, but the current LaFeO with higher gas response 3 Ethanol-based gas sensor element, whose optimum working temperature is LaFeO below 200°C 3 The ethanol-based gas sensor element either contains heavy metal elements such as Pb, which is not conducive to environmental protection, or contains rare earth precious metals such as Sm, and the cost is relatively high

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