The Effect of Ceria on the Dynamics of CuO-Cu2O Redox Transformation: CuO-Cu2O Hysteresis on Ceria

摘要

CuO supported on ceria and alumina is prepared by incipient wetness impregnation and its redox behavior is investigated by means of XRD, XPS and TPO experiments. CuO on ZrO2 and on ceria-zirconia are also synthesized for comparison. The support plays a major role on the dynamics of CuO-Cu2O transformation. On Al2O3 the formation of CuAl2O4 inhibits any oxygen exchange during TPO experiments, while on ceria, zirconia and ceria-zirconia supported catalysts CuO decomposition and re-oxidation take place with a hysteresis similar to that observed for Pd-PdO transformation. On CeO2 the hysteresis is significantly reduced, indicating a strong effect of ceria on CuO-Cu2O redox cycle.