Synthesis of highly active CuO–CeO2 nanocomposites for preferential oxidation of carbon monoxide at low temperatures

CuO–CeO2 nanocomposites were prepared by coprecipitation of nitrates at various pH values and used for preferential oxidation (PROX) of CO in a hydrogen rich gas. Precipitation at high pH led to a high concentration of CeO2 nucleation and abundant active Cui sites (Cu atoms at interface between CuO and CeO2) on prepared nanocomposites. The reducibility of CuiO and its turnover frequency for PROX were increased with the pH during preparation of nanocomposites. Catalysts coprecipitated at pH ⩾ 12 exhibited excellent CO conversion (>99%) and distinguished CO selectivity (88%) for PROX at a low reaction temperature of 125 °C.