In Situ EXAFS Study of the Sulfidation of an Hydrotreating Catalyst Doped with a Non Chelating Organic Additive

Abstract : An industrial alumina-supported CoMoP catalyst was impregnated (incipient wetness method) with an aqueous solution of diethyleneglycolbutylether (DEGbe) and then dried at 393 K overnight. After sulfidation under H2/H2S, this catalyst has a higher activity than the non impregnated CoMoP. In order to check if the presence of such an organic additive in contact with the oxidic form of the active phase influences the kinetics of sulfidation of the cobalt and the molybdenum, EXAFS spectroscopy (K-Co or K-Mo edges) experiments were performed in situ during the sulfidation of CoMoP + DEGbe catalyst and of the non DEGbe treated one. The results showed that the sulfidation of Co and Mo is inhibited by DEGbe up to 473 K. EXAFS helped to understand the role of the organic compounds added to the oxidic catalysts and to establish the role of the organic compound in the sulfidation of Co and Mo elements.