Preparation of Au nanoparticles with high dispersion and thermal stability by a controlled impregnation method for alcohol oxidation.

Gold nanoparticles are attractive in catalytic field due to their high activity and selectivity. However, dispersion and sintering resistance have been two of the biggest issues in catalysis for preparation of gold nanoparticles. In this paper, a controlled impregnation method was employed to prepare highly dispersed and thermally stable Au-based catalysts for aerobic oxidation of benzyl alcohol. The size of hydrotalcites (HTs)-supported Au nanoparticles was 2.8 nm at 300 °C of calcination temperature, which was 3.2 nm when calcination temperature was increased to 600 °C. The mechanism of forming metal nanoparticles was proposed. The high dispersion of Au was ascribed to the directing role of Cu and the interaction between Au (and Pt) and Cu. It was proposed that the thermal stability of Au nanoparticles was due to the simultaneous employment of multiple additional effects. The activity of Au nanoparticles was far higher than those prepared by traditional methods. Furthermore, the PtCu elements in Au nanoparticles were homogeneously distributed. In contrast, they were randomly distributed in Au nanoparticles prepared by the traditional method. [ABSTRACT FROM AUTHOR]