Hydrodesulfurization activity and electronic properties of molybdenum sulfide catalyst

Abstract

The relationship between the defect structure of molybdenum sulfide and its hydrodesulfurization (HDS) activity is examined. The S 2− ion vacancy concentration of the catalyst is adjusted by pretreatment in H 2 or H 2S and monitored by electrical conductivity measurements. Exposure of the catalyst to pulses of butyl mercaptan and hydrogen allows determination of the conversion rate and product distribution as a function of the electronic defect structures of the catalyst. The results demonstrate the existence of a “window” in catalyst composition for optimum HDS performance. During catalytic reaction, interface charge transfer is observed with gradual modification of the electronic properties of the catalyst and changes of its catalytic activity for HDS. The results indicate a close relationship between the density of S 2− ion vacancies and catalyst performance. The mechanism of catalytic HDS is examined in terms of the defect structure of the solid.