Activity behavior of samaria-doped ceria-supported copper oxide catalyst and effect of heat treatments of support on carbon monoxide oxidation

Activity behavior of CO oxidation was studied over samaria-doped ceria (SDC)-supported CuO catalysts. The material properties of the SDC support were changed by heat treatments, which were carried out by the variations of the calcination temperatures of SDC (500-1100degreesC) and the cooling methods (with quenching after calcination or without it). The X-ray diffraction, N-2 physisorption, N2O chemisorption, energy dispersive X-ray spectrum, carbon monoxide temperature-programmed reduction, and the activity test were carried out. The results showed that, when the calcination temperature of SDC was lower, its surface area was higher, and thus more interfacial active sites were formed over the CuO/SDC catalyst; this led to higher activity. Quenching after calcination was beneficial to increase the surface area of SDC and thus increase the activity of the CuO/SDC catalyst. It was also found that the specific activity of the interfacial active site was not affected by the heat treatment. The light-off of the CO oxidation activity of the CuO/SDC catalyst was observed at a temperature as low as 75degreesC. It was concluded that the concentration of the interfacial active sites was key for the occurrence of light-off. (C) 2002 Elsevier Science B.V. All rights reserved.