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

Based on first principles calculations of density functional theory, the adsorption behaviour of H2S on the surface of intrinsic and Pd loaded VO2 was studied. According to the analysis of the adsorption performance of H2S gas on intrinsic VO2, the adsorption process of H2S gas on the surface of intrinsic VO2 is spontaneous. In addition, we chose to load precious metal Pd on the surface of VO2 and found the best loading position. We used the best loading Pd site as the adsorption matrix, and calculated the adsorption behaviour of H2S gas on the Pd/VO2 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 VO2 surface loaded with Pd has stronger adsorption performance for H2S gas, which changed the adsorption performance of VO2 for H2S gas. Finally, we studied the optical properties of VO2 before and after adsorbing H2S and before and after loading Pd. We found that the order of response to visible light is as follows: VO2+Pd+H2S > VO2+Pd > VO2+H2S > VO2. Our results provide theoretical support for manufacturing suitable optical gas sensors. [GRAPHICS] .