Comparative study of different methods of preparing CuO-CeO2 catalysts for preferential oxidation of CO in excess hydrogen

Influence of preparation methods (i.e. co-precipitation, chelating, citric acid and critical phase) on the preferential oxidation of CO in excess hydrogen over CuO-CeO2 catalysts has been investigated. CuO-CeO2 catalysts are characterized by using BET, X-ray powder diffraction (XRD), UV Raman and temperature-programmed reduction (TPR) techniques. The catalyst prepared by chelating is most active for the preferential oxidation of CO. In addition, XRD, UV Raman and TPR show that the chelating method enhances the formation of defects of ceria and produces a synergic effect between the cycle of Cu1+/Cu2+ and that of Ce3+/Ce4+, which is beneficial to the improvement of the performance of CuO-CeO2 catalysts.

The CuO-CeO2 catalyst prepared by the chelating method is most active in preferential oxidation of CO. CO conversion over CuO-CeO2 catalysts prepared by the chelating method is 99.6% at the temperature of 120 °C, while CO conversions over the CuO-CeO2 catalysts prepared by the co-precipitation and critical-phase drying methods cannot reach 99% and that over the CuO-CeO2 catalysts prepared by the citric acid method is 99.2% at 160 °C. TPR, XRD and UV Raman results show that the chelating method enhances the formation of defects of ceria and produces a synergic effect between the cycle of Cu1+/Cu2+ and that of Ce3+/Ce4+, which is beneficial to the improvement of the performance of CuO-CeO2 catalysts. Figure optionsDownload as PowerPoint slide