High Catalytic Activity in the Phenol Hydroxylation of Magnetically Separable CuFe₂O₄–Reduced Graphene Oxide

We reported a highly active CuFe 2 O 4 catalyst modified with reduced graphene oxide (CuFe 2 O 4 –RGO) by a solvothermal method. The composite catalyst was fully characterized by FTIR, XRD, Raman, TEM, and XPS, which demonstrated that the CuFe 2 O 4 nanoparticles (NPs) with a diameter of approximately 17.8 nm were densely and compactly deposited on the reduced graphene oxide (RGO) sheets. The as-prepared CuFe 2 O 4 –RGO composites were used to catalyze phenol hydroxylation for the first time, which exhibited great catalytic activity. The conversion rate of phenol to dihydroxybenzenes reached 35.5% with a selectivity of 95.2% obtained, which is much higher than for reported systems (25.0%). The catalytic activity remained high after six cycles. More importantly, the catalyst can be easily recovered due to its magnetic separability and the organic solvent-free nature of the phenol hydroxylation process. A possible mechanism in phenol hydroxylation by H 2 O 2 over CuFe 2 O 4 –RGO 20 catalyst was also proposed.