Carbon-encapsulated Fe3O4 for catalyzing the aerobic oxidation of benzyl alcohol and benzene

A carbon-encapsulated Fe3O4 (Fe3O4@C) was prepared by a simple solvothermal method. The obtained Fe3O4@C was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption–desorption isotherm measurement. The core–shell structured Fe3O4@C could efficiently catalyze the solvent-free aerobic oxidation of benzyl alcohol to benzaldehyde with ambient O2 as the oxidant. The uniform interface between the core Fe3O4 and the shell C accounted for the superior catalytic activity of Fe3O4@C. A possible catalytic process following the known Mars-van Krevelen mechanism was described. The target catalyst could be magnetically recycled and exhibited good potential for catalyst reuse. Besides, the activity of Fe3O4@C was also investigated for catalyzing the reductant-free aerobic hydroxylation of benzene to phenol with O2 as the oxidant.