Large size Pd NPs loaded on TiO₂ as efficient catalyst for the aerobic oxidation of alcohols to aldehydes

Anti-sintering Pd/TiO₂ catalysts have been prepared by different methods and systematically characterized. Compared with the catalysts prepared by the heterogeneous deposition precipitation (HDP) method and wetness impregnation (WI) method, the catalyst prepared by the deposition precipitation (DP) method could give higher content of Pd species. Pd/TiO₂ prepared by DP method shows much higher activity than other catalysts in liquid phase oxidation of benzyl alcohol to benzyl aldehyde. The average particle size of Pd nanoparticles (NPs) is 15 nm. XPS results indicate that though Pd^{2 +} species have been reduced to Pd⁰ after use, the activity of catalyst is not affected, which has never been reported in the literature.