Ab Initio Molecular Dynamics Study of H2S Dissociation on the Fe(110) Surface

The adsorption of H2S on Fe(110) is examined using ab initio molecular dynamics at 298, 800, 1000, and 1808 K. The stages of the reaction are identified and compared for different temperatures. At 298 K, H2S adsorbs dissociatively, to leave adsorbed S and H atoms on the surface. At higher temperatures, H2S dissociation is followed by H diffusing into the subsurface layers. After complete dissociation at the Fe melting point, the H atoms recombine into molecular hydrogen which desorbs to leave S on the surface. The dissociation mechanism at each temperature is found to be different with the structure and position of the adsorbate on the surface being affected by reconstruction of the surface Fe atoms at higher temperatures.