Enhanced H2S gas sensing of Pd functionalized NiO thin films deposited by the magnetron sputtering process

Abstract

This letter presents the H2S gas sensing results of Pd-decorated NiO (Pd/NiO) thin films deposited by the magnetron sputtering process. The presence of the Pd catalyst enhanced the H2S sensing capability of NiO thin films in terms of high response (Rg/Ra ratio ∼ 15) and relatively lower optimum operating temperature (Topt) at 250 °C for 100 ppm H2S gas concentration. Further, the Pd/NiO thin films also exhibited a fast response/recovery time of ∼65 s/29 s, low detection concentration (∼2 ppm), good stability, and high selectivity at Topt (i.e., at 250 °C) towards H2S gas. The significantly improved H2S gas sensing properties of the Pd/NiO thin films can be mainly attributed to the modulation of the potential barrier and an increase in the specific surface area for the target gas adsorptions. Thus, the current work offers the development of highly responsive Pd functionalized NiO thin films for H2S gas sensors, which ensures low power requirements.