Selective catalytic oxidation of carbon monoxide with carbon dioxide, water vapor and excess hydrogen on CuO-CeO2 mixed oxide catalysts

A series of CuO-CeO2 catalysts with Cu content in the range of 5-50 at.% (the atomic percent of Cu/(Cu + Ce)) were prepared by co-precipitation method. The catalysts were tested for CO oxidation and selective CO oxidation with CO2, H2O and excess H2. The catalysts were highly active in the CO oxidation and also active and remarkably selective in the selective oxidation. CO2 and H2O, however, decreased the catalyst activity; between CO2 and H2O, H2O decreased the activity more than CO2. Among the catalysts, the 10 at.% Cu catalyst outperformed all the other catalysts in the CO oxidation without CO2 and H2O in the feed, whereas the 20 at.% Cu exhibited the highest activity in the selective CO oxidation. This change in the optimum Cu content could be ascribed to the adverse effect of H2O on the activity that was dependent on the Cu content of the catalysts.