Detection Characteristics and Sensing Mechanism of Metal-doped SnO2-based H2 Gas Sensor

Dissolved gas analysis (DGA) is an important means of condition monitoring of oil-immersed power transformer. SnO
₂
gas sensor is a common sensor for main dissolved fault characteristic gases in transformer oil, and metal doping can significantly improve its detection characteristics. However, the mechanism of metal doping modification of SnO
₂
-based gas sensing materials is few and not clear yet. In this paper, the detection characteristics and sensing mechanism of metal-doped SnO
₂
based sensitive materials to H
₂
was systematically studied. It can be concluded that metal doping can reduce the working temperature of SnO
₂
, increase the concentration characteristics of gas and accelerate the response speed. SnO
₂
doped with Ag and Pd can effectively detect H
₂
at concentrations below 1 μL/L. By comparing the microscopic simulation results with the macroscopic detection characteristics, a metal doping modification mechanism was established, which was related to the bandgap width and the optimum working temperature, gas adsorption energy and response-recovery characteristics. The accuracy and feasibility of the first-principles calculation for gas sensing mechanism analysis were verified. This research results have important theoretical and practical significance for improving the detection level of SnO
₂
-based gas sensor to transformer fault characteristic gases.