CO oxidation over Pt/SnO2 catalysts

The influence of treatment conditions on Pt/SnO2 properties and its catalytic activity in CO oxidation was investigated. It was found that the temperature and atmosphere of catalyst heating had a great impact on the active phase dispersion, the chemical composition of the surface layer and the O-2 adsorption capacity of the Pt/SnO2 catalysts. TOF-SIMS analysis and XRD measurements showed that the heat treatment in an atmosphere of H-2 promotes the formation of bimetallic compounds of Pt-Sn and different species such as PtOH, PtO2, PtO2H, PtOCl, PtSnO, PtSnOH. It was stated that their presence significantly affects the activity of the catalyst in the CO oxidation. The catalyst capacity of O-2 adsorption varied depending on the treatment conditions. The catalyst treated at 600 A degrees C in oxygen showed the greatest ability of oxygen adsorption. A significant difference in the activities between the catalyst samples heated in O-2 or H-2 atmosphere was found. The highest activity was obtained for 1%Pt/SnO2 sample treated in oxygen at 700 A degrees C. The treatment in hydrogen above 100 A degrees C caused a decrease in the catalyst activity.