A computational study of hydrogen sulfide adsorption on transition and noble metal surfaces

Computational studies have been conducted to investigate the reaction mechanism and activation barriers for H2S adsorption and subsequent dissociation on transition and noble metal surfaces using a Vienna Ab-initio Simulation Package (VASP) based on density functional theory. The transition metals that have been studied include nickel, palladium and platinum and noble metals include copper, silver and gold. It was observed that the H2S dissociation is a facile process over transition metal surfaces and encounters high activation barriers over the noble metal surfaces.;Next, the chemical bond analysis was performed for M-H2S systems where M is a single metal atom, M12-H2S cluster systems (M12 is 12 metal atom cluster) and the periodic systems where H 2S is adsorbed over the metal surfaces, to compare the nature of M-S bond with M in different environments. It was observed that a M-S bond in various systems is stabilized due to the rearrangement of electron density from occupied metal d-orbitals and non-bonding orbital of H2S to the empty s- and p-orbitals of metal.