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

•Large sized Pd NPs loaded on TiO2 are prepared by different methods.•Both Pd0 and Pd2 + are active in alcohol oxidation.•The catalyst prepared by DP method could be reused 5 times.

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 Pd2 + species have been reduced to Pd0 after use, the activity of catalyst is not affected, which has never been reported in the literature.

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