Adsorption and decomposition of H2S on the Ni(111) and Ni(211) surfaces: A first-principles density functional study

The adsorption and dissociation of H2S on Ni(1 1 1) and Ni(2 1 1) were both studied using first-principles density functional calculations (DFT-GGA) and periodic supercells. In this study, the adsorption configurations and structural parameters of H2S, HS, S and H have been given on Ni(1 1 1) and Ni(2 1 1). And the co-adsorption behaviors of HS + H and S + H were also investigated. The orders of the adsorption energy for these substances on Ni(1 1 1) and Ni(2 1 1) are both as follows: H2S, H, HS, S. In addition, it is found that the dissociation of H2S on the Ni metal surface would occur easily through the study of the dissociation mechanism of H2S. It is worth noting that the difference in energy variation of the first H-S fracture of H2S (H2S -> H + HS) is small on Ni (1 1 1) and Ni(2 1 1)( - 1.04 eV and -1.12 eV). However, the energy barrier of the dissociation of the second H-S(HS -> H + S) on Ni(2 1 1) surface is greater than that of Ni(1 1 1), which was explained in structure, mulliken charge and PDOS. These results provide more information for further understanding the mechanism of sulfur poisoning on Ni catalyst.