Carbon Catalyzed Hydroxylation of Benzene with Dioxygen to Phenol over Surface Carbonyl Groups

Carbon materials are promising environmentally-benign heterogeneous catalysts but design of effective carbon catalysts with comparable or even superior performance to metal-based ones is highly challengeable. Herein, N-doped mesoporous carbons with the surface enriched with abundant oxygen species were synthesized by a facile hydrothermal doping strategy in the self-assembly of phenolic resin, followed with a carbonization process. Direct hydroxylation of benzene to phenol with O ₂ as the sole oxidant was effectively catalyzed by these carbons, affording a yield superior or comparable to previous efficient transition metal and even noble metal-based catalysts. The catalyst is facilely recovered and stably reused. The surface carbonyl groups are the active sites for O ₂ activation (rate determining step) to generate hydroxyl radicals, which are the reactive oxygen species to oxidize the benzene. This methodology is readily extendable to the oxidation of various other benzene derivatives.