Comparative study of unsupported and supported Co-Mo hydrodesulphurisation catalysts

Catalytic activities of unsupported and alumina- or silica-supported cobalt-molybdenum catalysts in the oxidic and sulphided form are compared. Silica-supported catalysts behave essentially as unsupported catalysts. The behaviour of alumina-supported catalysts is quite different. The synergistic effect is much stronger, especially in the sulphided form, and the domain in which the synergism is exhibited is much broader. In addition, alumina brings about a strong hydrogenating activity. ESCA measurements have helped to investigate further the interaction between the cobalt-molybdenum system and alumina.