First-principles study of H2S sensing mechanism on the Pd/VO2 surface

Abstract

ABSTRACT Based on first principles calculations of density functional theory, the adsorption behaviour of HS on the surface of intrinsic and Pd loaded VO was studied. According to the analysis of the adsorption performance of HS gas on intrinsic VO, the adsorption process of HS gas on the surface of intrinsic VO is spontaneous. In addition, we chose to load precious metal Pd on the surface of VO and found the best loading position. We used the best loading Pd site as the adsorption matrix, and calculated the adsorption behaviour of HS gas on the Pd/VO surface. The results showed that the active site was transferred from the B-1 site to the H-1 site due to the loading of the precious metal Pd. Further analysis found that the VO surface loaded with Pd has stronger adsorption performance for HS gas, which changed the adsorption performance of VO for HS gas. Finally, we studied the optical properties of VO before and after adsorbing HS and before and after loading Pd. We found that the order of response to visible light is as follows: VO+Pd+HS> VO+Pd> VO+HS> VO. Our results provide theoretical support for manufacturing suitable optical gas sensors.