Catalytic Activity and Characterization of Oxygen Mobility on Pt/Ce0.75Zr0.25O2 Catalyst by Isotopic Exchange with 18O

The Ce0.75Zr0.25O2-supported Pt catalysts with different Pt loadings were prepared by the impregnation method. The results of isotopic exchange of 18O, temperature-programmed surface reaction of ethanol (C2H5OH-TPSR), temperature-programmed desorption of CO (CO-TPD), and temperature-programmed reduction of H2 (H2-TPR) show that the Pt phase is amorphous and well dispersed on the support surface. The C2H5OH-TPSR and CO-TPD results show a good correlation of the amount of desorbed CO2 with the catalytic activity for ethanol or CO oxidation. The Pt/Ce0.75Zr0.25O2 catalyst has improved activity for ethanol or CO oxidation, and the catalytic activity is related to the Pt loading. The results of the ethanol or CO oxidation and isotopic exchange of 18O2 show that the oxygen exchange capacity is responsible for the improved catalytic activity. The sample with the best catalytic activity has the highest surface oxygen diffusion rate.