Enhanced performance of binary WO3/N-doped carbon composites for the catalytic oxidation of benzyl alcohol under mild conditions

Abstract

In this work, a series of N-doped carbon supported WO3 composite catalysts were successfully prepared via a hydrothermal and subsequent calcination method. The obtained WO3/N-doped carbon composites outperformed the bare WO3 and bare N-doped carbon for the selective oxidation of benzyl alcohol to benzaldehyde under mild and green reaction conditions (no base additives, water as solvent, and H2O2 as oxidant). It was found that the superior catalytic performance could be ascribed to the synergistic effect and strong interaction between WO3 and N-doped carbon among the composites. N-doped carbon impeded the aggregation of WO3 nanoparticles, and the graphitic and pyrrolic N species of N-doped carbon might provide main active sites for the immobilization of WO3 nanoparticles. Under the optimum reaction conditions, the yield of benzaldehyde was achieved as 94.6% within 4 h. The recycling test indicated that the catalyst could be reused for seven times without obvious activity loss. Besides, a possible reaction mechanism for this transformation was proposed. This work might give some insights into the design of heterogeneous composite catalysts for the selective oxidation of benzyl alcohol under mild conditions.