Palladium Doped SnO2 Nanocrystals for Enhanced Methane Gas Sensing Application

Methane (CH4) is one of the major characteristic gases of transformer fault as it dissolve in transformer oil and can effectively reflect discharge fault and the overheating of the oil-paper. Thus, fabrication of highly efficient and sensitive Gas sensor is crucial in the online monitoring of methane in transformer oil. In this work, we prepared a methane sensing material by surface deposition of the aqueous solution of palladium ion (Pd2+) onto tin dioxide (SnO2) nanocrystals, and we tested the performance of the fabricated sensor in detecting CH4. It was found that after Pd2+ doping, the sensitivity of the sensor toward 100 mu L/L CH4 could reach up to 10.28. Model calculations based on first principle showed that doping with Pd2+ brought the Fermi level into the conduction band of SnO2 and reduced the direct band gap, which increased the conductivity of SnO2, promoted electron transition, and ultimately improved the sensitivity of the sensor.