Hydrodesulphurization of Thiophene by Transition Metal Sulphides: The Electronic Basis for Catalytic Activity

Transition metal sulphides (TMS) have the ability to catalyze the hydrodesulphurization (IDS) of thiophenes occurring in oil. The catalytic activity varies strongly across the TM series, and can in some cases be significantly enhanced by the addition of promotor elements (e.g. Co/Ni in MoS2).From a series of density functional (DF) scattered-wave electronic structure calculations on first, second and third row TMS, electronic parameters related to the catalytic activity have been identified. The occupation and topology of metal-sulphur antibonding orbitals near the Fermi level are particularly important. An activity parameter, I, which is a measure of the strength of the interaction between metal d and sulphur 3p electrons, correlates well with the experimental HDS activities.