CO Oxidation Activity of a Au/Ceria-Zirconia Catalyst Prepared by Deposition-Precipitation with Urea

The activation of a 2.6 wt% Au/Ce0.62Zr0.38O2 catalyst prepared by deposition-precipitation with urea is investigated. At 298 K, the activity for CO oxidation of the as-prepared sample is very low; it is significantly increased when heated at 418 K, under the reaction mixture, and much strongly when pre-treated under flowing O-2(5%)/He, at 523 K. As revealed by XPS, FTIRS, HAADF-STEM, and HRTEM studies, the activation process consists of the transformation of the initial urea-containing Au(III) precursor deposited on the support into a highly dispersed metal phase (Au nano-particle mean size: 1.8 nm).