Water-gas shift reaction over sulfided molybdenum catalysts I. Alumina, titania and zirconia-supported catalysts

Three series of Ni-Mo-sulfided catalysts supported on gamma-Al2O3, TiO2 and ZrO2 were tested in the water-gas shift (WGS) reaction with sulfided feed. Characterization of oxidized forms of the WGS catalysts has been carried out using thermogravimetry, X-ray diffraction (XRD), BET, ammonia-temperature-programmed desorption (TPD), pyridine-FT-IR, TPR. The highest catalytic activity was found for Mo catalysts based on TiO2 and Ni-containing TiO2 supports. This is related to better homogeneity in the coordination of Mo species on titania than that on alumina and zirconia. The presence of Ni2+ enhances the reducibility of Mo species and is responsible for synergy of Ni-Mo-S-based catalysts and better catalytic performance. (C) 2000 Elsevier Science B.V. All rights reserved.