No abstract

No abstract

No abstract

Publication costs assisted by the University of Georgia X-ray photoelectron spectroscopy (ESCA) has been used to study the surface reactions of a commercial cobalt-molybdenum-alumina catalyst. Reduction of the catalyst in hydrogen produced a mixture of molybdenum oxidation states: Mo(VI), Mo(V), and Mo(IV). The relative amount of molybdenum in each state was determined as a function of reduction time and temperature. Exposure of fired catalysts to thiophene in an inert atmosphere showed that only thiophene adsorption occurred. In contrast fired, prereduced catalysts showed both thiophene adsorption and desulfurization capability in an inert atmosphere. The molybdenum of the catalyst was effectively sulfided in either thiophene/H2 or H2S/H2. However, prereduced catalysts sulfided to a lesser extent than catalysts that had only been fired. In no case was complete sulfiding of the molybdenum observed. The cobalt of the catalyst showed little change on treatment with either hydrogen or thiophene/H2. This was in contrast to application of H2S/H2 which sulfided the cobalt of the catalyst more rapidly than the cobalt in cobalt aluminate.

No abstract