Cluster approach of active sites in an MoS2 catalyst

The present paper reports a Density Functional Theory (DFT) study of a Mo12 S24 cluster as a model of the active phase in hydrodesulphurisation (HDS). Different types of sulphur vacancies are considered and compared. The inter action of a thiophene molecule with a double vacancy is simulated leading t o the determination of a stable configuration which corresponds to a flat a dsorption on the edge of the MoS2 sheets. The dissociative adsorption of mo lecular hydrogen on a double vacancy is also considered.