Palladium on graphene as efficient catalyst for solvent-free aerobic oxidation of aromatic alcohols: Role of graphene support

Abstract

Palladium catalysts supported on different carbon materials, i.e. graphene, carbon nanotube and activated carbon, have been prepared by improved wet impregnation and employed in the solvent-free aerobic oxidation of aromatic alcohols using molecular oxygen as oxidant. High catalytic activity as well as high selectivity to corresponding carbonyl compounds can be obtained on Pd/graphene. Typically, an extremely high turnover frequency of 30,137mol/hmolPd is observed in the aerobic oxidation of benzyl alcohol to benzaldehyde using Pd/graphene as catalyst. Palladium catalysts on different carbon supports are fully characterized by a series of techniques, e.g. Raman, XRD, SEM, TEM, TG, XPS, FTIR spectra of benzyl alcohol adsorption and O2-TPD. Based on the catalytic and characterization results, the superior reactivity of Pd/graphene in the aerobic oxidation of aromatic alcohols is attributed to the promotion role of graphene support in the adsorption of reactant alcohol and oxygen.