Mechanochemical synthesis of CuO-CeO2 catalysts for the preferential oxidation of CO in the presence of H2

Abstract

Mechanochemical activation was used in the synthesis of CuO-CeO2 catalysts for the preferential oxidation of CO in the presence of excess H2. Catalysts similar in properties to supported CuO/CeO2 systems were prepared from mixtures of copper oxide (5 or 10 wt % CuO) and cerium dioxide with the use of mechanochemical activation. It was found that the time of mechanochemical activation influences the catalytic properties: a maximum conversion of CO into CO2 (97%) at 140°C was achieved with a sample of 10 wt % CuO-90 wt % CeO2 after mechanochemical activation in a ball mill for 90 min. Changes in the phase compositions of the catalysts depending on mechanochemical activation time and reaction mixture composition were studied by X-ray diffraction. The interaction of the oxides of copper and cerium in the process of mechanochemical activation with the formation of new Cu-O-Ce surface structures, which, supposedly constitute active sites for CO oxidation, was found using differential scanning calorimetry and differential thermogravimetric analysis.