Structural features and catalytic performance in CO preferential oxidation of CuO???CeO2 supported on multi-walled carbon nanotubes

Multi-walled carbon nanotube (MWCNT) supported CuO–CeO2 catalysts were prepared using an impregnation method aided by an ultrasonication treatment. The structural features of the catalysts were extensively characterized by XRD, TGA, H2-TPR, XPS, TEM and Raman spectroscopy. The catalytic performance in the preferential oxidation of CO in a H2-rich stream was extensively investigated with respect to the influences of Cu/Ce ratios, the different support materials and the presence of CO2 and H2O in the feed stream. In contrast to those supported on other materials, the catalytic performance was greatly enhanced for the MWCNT-supported CuO–CeO2 catalysts, which was discussed in terms of the synergistic interactions between Cu–Ce mixed oxides and MWCNT. The optimized catalyst with a Cu/Ce ratio of 5/5 can achieve complete CO conversion and high selectivity toward CO2 in a wider temperature range as well as favorable performance under the simulated reformatted gas mixture. The deactivation of CuO–CeO2 catalysts supported on MWCNT at elevated temperatures was also discussed in relation to the temperature-dependent in situ XAFS spectra during CO-PROX reaction.