Adsorption of thiophene on the catalytically active surface of MoS2:: An ab initio local-density-functional study

The adsorption of thiophene on the catalytically active MoS2(010) surfaces has been studied using ab initio local-density-functional molecular dynamics. It is shown that thiophene adsorbs in an eta(5) configuration with the molecular ring parallel to the surface, centered above a coordinatively unsaturated Mo atom, and with the sulfur atom in a binding position between two Mo surface atoms. This configuration provides not only the highest adsorption energy, but activates in addition the thiophene molecule with respect to both C-S bond cleavage (and hence desulfurization) and hydrogenation. Hence it represents a realistic scenario for the first step in catalytic hydrodesulfurization. [S0031-9007(98)05327-7].