Preferential CO oxidation on Pt-Cu/Al2O3 catalysts with low Pt loadings

The higher CO conversions at low temperatures were obtained for the Pt0.5Cu8/Al2O3 sample, probably due to the simultaneous formation of small Pt crystals in close contact with CuO. The XPS results show that a strong surface enrichment in Pt takes place in all the samples. Thus, a small loading of the noble metal is enough to obtain effective catalysts. The surface Pt enrichment observed is most probably due to the impregnation of the Pt salt onto the Cu/Al2O3 solid, with a relatively low calcination temperature (300 °C) that prevents the formation of bulky CuAl2O4 spinel crystals.