High dispersed Pd supported on CeO2 (100) for CO oxidation at low temperature

Nanostructured CeO2 with morphologies of nanorod, nano-cube, and nano-octahedron were successfully synthesized and the effects of cerium morphology were investigated on the catalytic efficiency of Pd/CeO2 for CO combustion. The light-off curves showed that Pd supported on rod-like CeO2 (1 0 0) plane had excellent performance. Subsequently, different contents of Pd were loaded on nanorod CeO2 to investigate the effect of Pd and CeO2 support interaction on the catalytic activity. Under optimal deployment, CO can be completely converted below 50 degrees C. Through cautious analysis of SEM, HAADF-STEM, XRD, XPS, and EDS patterns, Pd was proved to be highly dispersed on the surface of CeO2 carrier (1 0 0) in the form of PdO and PdxCe1-xO2-sigma. As a result of the strong metal-support interaction, Pd2+ ions substituted for Ce4+, -Pd2+-O2- -Ce4+- species were formed for enhancing CO oxidation. Simultaneously, the generation of Ce3+/Ce4+ ion pairs can be regulated by adjusting the proportion of Pd. Further in situ DRIFTS characterization revealed that in this reaction system, highly dispersed Pd on the surface of Pd/R-CeO2 could increase the concentration of Ce3+ on the surface, and lattice oxygen was activated in the oxidation reaction to generate abundant oxygen vacancies, which can promote the generation of active centers synergistically, thereby greatly enhancing the reaction activity.