Effect of preparation methods on the structure and redox behavior of platinum–ceria–zirconia catalysts

Abstract

Abstract Platinum was introduced into ceria–zirconia solid solutions to form nominal Ce 0.66 Zr 0.32 Pt 0.02 O 2 solid solutions by sol–gel. It was found that, through sol–gel method, the Pt ions could be inserted into the ceria lattice according to the results of XRD, XPS and TPR analyses. This brought about a different synergistic effect between the Pt and Ce components in Ce 0.66 Zr 0.32 Pt 0.02 O 2 compared with the Pt/Ce 0.67 Zr 0.33 O 2 system prepared by traditional impregnation, such as increased the oxygen mobility in ceria–zirconia solid solutions and improved the stability of metallic state for platinum at high temperature. The lower surface Pt content leads to a worse three-way catalytic activity over the Pt-doped sample at low temperature. However, it features a better thermal stability after aging at 950 °C for 20 h, implying a self-generation mechanism of noble metals. This, in return, provides this material with a potential to be used in eliminating pollutants from auto exhaust.