Dynamic oxygen storage and release over Cu 0.1Ce 0.9O x and Cu 0.1Ce 0.6Zr 0.3O x complex compounds and structural characterization

Abstract

Cu 0.1Ce 0.9O x and Cu 0.1Ce 0.6Zr 0.3O x 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 Cu O and Ce O 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 Cu 0.1Ce 0.9O x and Cu 0.1Ce 0.6Zr 0.3O x are characterized with the fluorite-type cubic structure similar to CeO 2. From XPS, it can be concluded that Cu 2+ exists on the surface of Cu 0.1Ce 0.9O x and Cu 0.1Ce 0.6Zr 0.3O x samples. The EPR studies show that there are three types of Cu 2+ species: Cu 2+ clusters, isolated Cu 2+ ions and Cu 2+ dimers in these composite oxides.