SURFACE SCIENCE MODEL OF A WORKING COBALT-PROMOTED MOLYBDENUM SULFIDEHYDRODESULFURIZATION CATALYST - CHARACTERIZATION AND REACTIVITY

Surface science models of silica- and alumina-supported CoMoS catalyst s have been made by impregnating thin SiO2 and Al2O3 films with a solu tion of nitrilotriacetic acid (NTA) complexes of cobalt and molybdenum . XPS spectra indicate that the order in which cobalt and molybdenum t ransfer to the sulfided state is reversed with respect to oxidic Co an d Mo systems prepared by conventional methods, implying that NTA compl exation retards the sulfidation of cobalt to temperatures where MoS2 i s already formed. Catalytic tests show that the CoMoS model catalysts exhibit activities for thiophene desulfurization and product distribut ions similar to those of their high surface area counterparts.