Investigation on adsorption and decomposition of H2S on Pd (1 0 0) surface: A DFT study

Abstract

Density functional theory (DFT) together with periodic slab models was employed to investigate the adsorption and decomposition of H2S on the Pd (1 0 0) surface. Different kinds of possible modes of H2S and HS species adsorbed on the surface were identified. It was found that H2S prefers to adsorb on the top sites, while HS, S and H adsorb preferentially on the hollow sites. Additionally, the optimum co-adsorption configurations for HS/H and H/S were determined. It was revealed that the co-adsorbed species repel each other slightly on the Pd (1 0 0) surface. Finally, the potential energy profile of H2S dissociation on the Pd (1 0 0) surface was constructed. The energy barriers of the first and second H-S bond scission are similarly low, implying that the dissociation of H2S on the Pd (1 0 0) surface is facile both kinetically and thermodynamically. The distinct differences over Pd (1 1 1) and Pd (1 0 0) surface suggests that the decomposition of H2S over Pd-based catalyst is a structure-sensitive reaction.