Characterization and H2S gas sensing characteristics of Au-decorated ZnO nanorods prepared by a two-step wet method

H2S is a highly corrosive and toxic gas, necessitating the realization of sensitive and selective sensors for its detection. In this study, we employed gold (Au) decoration on zinc oxide (ZnO) nanorods (NRs) for H2S gas sensing. The Au-decorated ZnO (Au-ZnO) NRs were synthesized via a hydrothermal method at 90 degrees C for 5 h. Various characterizations confirmed the formation of Au-ZnO NRs with an NR morphology, uniform dispersion of Au nanoparticles (NPs) on ZnO NRs, and the desired chemical composition. H2S sensing was conducted at different temperatures for pristine and Au-ZnO NR-based gas sensors. Both sensors manifested optimal performance at 250 degrees C. The responses to 10 ppm H2S for the pristine and Au-ZnO NRs sensors were 4.93 and 89.57, respectively, underscoring the significant enhancement in H2S sensing due to Au decoration. Furthermore, the Au-ZnO NR sensor could detect H2S at concentrations as low as 200 ppb, demonstrating high selectivity to H2S. The improved sensing capability is attributed to the catalytic effect of Au on H2S, the generation of Au-ZnO heterojunctions, and the creation of oxygen vacancies. This study highlights the promising potential of Au decoration for enhancing H2S sensing capabilities.