A metal-/additive-free system for oxygen-mediated hydroxylation of benzene over polyfuran-functionalized hydrothermal carbocatalyst

Direct benzene hydroxylation with dioxygen (O₂) is among the most promising alternative pathways for green phenol production, but efficient catalysis systems usually involve metal species or other additives such as sacrificial agents. In this work, we designed a carbon catalyst from the hydrothermal treatment of biomass-derived sucrose and constructed a metal-/additive free heterogeneous catalytic system for benzene hydroxylation to phenol with O₂. The champion carbon sample gave a high phenol yield of 13.4%. The catalyst was facilely recovered and reused without apparent deactivation. There abundant oxygen functional groups such as phenolic and quinone carbonyl groups served as the active sites and polyfuran units accelerated the O₂ adsorption and activation. The synergistic effect of these surficial organic groups is conducive to the formation of reactive oxygen species, hydroxyl radicals, which effectively oxidized the benzene to phenol.