Structural determination of palladous oxide-ceria nanosystem supported on γ-alumina

Recently great efforts are being devoted to develop new methods of preparation of high-disperse Pd-CeO2 containing nanosystems stabilized on an oxide matrix. A new approach of synthesis consists in using the heterometallic PdII2CeIV2(μ-OOCMe)12(H2O)2 complex as a precursor to anchor Pd nanoparticles on the surface of γ-alumina in direct contact with CeO2. The present work is devoted to a structural study of this disperse Pd-CeO2 containing nanosystem after oxidative or reductive pretreatments in comparison with monometallic alumina-supported samples by XAFS and TEM. A strong interaction between Pd and ceria in the catalyst produced in the studied system affects reducibility of both PdO and CeO2, which in turn results in an increased low-temperature activity in CO oxidation along with a dramatic change of the ignition-extinction curve.