Preferential oxidation of CO in H2 over CuO-CeO2 catalysts

CuO-CeO2 catalysts prepared by the urea gelation/co-precipitation (UGC) method were studied for the preferential oxidation of CO in H2. The activity and selectivity of these catalysts are among the best reported to date for application to reformate-type gas mixtures. For a material calcined at 650 °C, ∼5 at.% Cu content is sufficient for maximum activity. Cu–O–Ce phases, comprising copper oxide clusters strongly associated with ceria, are proposed as the active sites for the reaction. No inhibition by CO2 is observed at temperatures above 140 °C, but the combined effect of H2O and CO2 is stronger, requiring operation at 165 °C for 99% CO conversion and 65% selectivity.