One-step preparation of flexible rGO/ZnO gas sensors for ppm-level H₂S detection

Accurately detecting low concentrations (ppm levels) of hydrogen sulfide (H₂S) is paramount for maintaining production process stability and safeguarding human health. In this work, graphene electrodes were prepared on flexible PI films by laser direct writing technique, and rGO/ZnO was prepared by one-step hydrothermal method, which was coated on the surface of graphene electrodes by drop-coating method, and finally, a gas sensor for detecting H₂S was obtained. Performance tests showed that all rGO/ZnO sensors responded effectively to 10 ppm H₂S at 140 °C. Notably, the 10% rGO/ZnO sensor exhibited responses of 1.2 at 140 °C and 1.53 at 180 °C. They displayed qualities of commendable selectivity, rapid response, and recovery times. Furthermore, the study delves into the mechanism of rGO/ZnO on H₂S gas and explains the electron transfer between the rGO/ZnO surface and H₂S by calculations combined with spin-polarized density-functional theory (DFT). The experimental findings represent a positive contribution to advancing gas sensors tailored for ppm-level H₂S detection.