Lj. Feng et al., ULTRAFINE CATALYSTS FOR HYDRODESULFURIZAT ION .2. SURFACE-PROPERTIES OF UFP-MO AL2O3 CATALYSTS/, Gaodeng xuexiao huaxue xuebao, 16(1), 1995, pp. 103-106
XPS was used for determining the surface properties of UFP-Mo/Al2O3. I
t is shown that all molybdenum existed in Mo6+ form on the surface of
oxidized UFP-Mo/Al2O3 catalysts, while a mixture of Mo6+, Mo4+, S6+ as
well as S2- was observed on the surface of the catalysts after HDS re
action. The ratio of Mo and S species with different valences ispronou
ncedly affedted by the preparation method and the Mo loading. The port
ion of Mo6+ and S6+ decreases with increasing Mo loading. The contents
of Mo6+ and S6+ Of s-UFP-MO/Al2O3 catalysts are higher than those of
i-UFP-Mo/Al2O3 for the same Mo loading.