Dynamic oxygen storage and release over Cu0.1Ce0.9Ox and Cu0.1Ce0.6Zr0.3Ox complex compounds and structural characterization

Cu0.1Ce0.9Ox and Cu0.1Ce0.6Zr0.3Ox samples prepared by sol–gel method are tested for the dynamic oxygen storage capacity (DOSC) and rate (DOSR). The results show that synergetic effects between CuO and CeO contribute to the majority of DOSC and DOSR performances at low temperature, and the DOSC and DOSR of these materials can be enhanced by the Zr addition. Both materials are characterized by X-ray diffraction (XRD), Raman, temperature-programmed reduction (TPR), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS). XRD and Raman results indicate that Cu0.1Ce0.9Ox and Cu0.1Ce0.6Zr0.3Ox are characterized with the fluorite-type cubic structure similar to CeO2. From XPS, it can be concluded that Cu2+ exists on the surface of Cu0.1Ce0.9Ox and Cu0.1Ce0.6Zr0.3Ox samples. The EPR studies show that there are three types of Cu2+ species: Cu2+ clusters, isolated Cu2+ ions and Cu2+ dimers in these composite oxides.