Adsorption and dissociation of H2S on Rh(100) surface by First-principle study

Abstract

The adsorption and dissociation of H2S on Rh(100) surface have been investigated using self-consistent periodic density functional theory. The adsorption mechanisms on Rh(100) surface of H2S, HS, H and S were examined. It is found that H2S is weakly adsorbed on bridge, top and hollow sites with their adsorption energies of −0.98, −0.86 and −0.82eV, respectively. In contrast to H2S, HS is strongly chemisorbed on Rh(100) surface at hollow, top and bridge site with the adsorption energies of −4.33, −4.31 and −3.85eV, whereas S and H preferred to be absorbed at hollow site. By using climbing nudged elastic band method (CI-NEB), we found the four most feasible paths for H2S dissociation on Rh(100), with energy barriers of 0.19eV, 0.25eV, 44meV and 98 meV, respectively. The energy barrier to break the S-H bond of HS with H co-adsorption or without H co-adsorption was almost the same low. This study reveals that H2S decomposition on Rh(100) surface is a facile process both kinetically and thermodynamically.