C₃N₄-H₅ PMo₁₀V ₂O₄₀: A dual-catalysis system for reductant-free aerobic oxidation of benzene to phenol

Hydroxylation of benzene is a widely studied atom economical and environmental benign reaction for producing phenol, aiming to replace the existing three-step cumene process. Aerobic oxidation of benzene with O ₂ is an ideal and dream process, but benzene and O₂ are so inert that current systems either require expensive noble metal catalysts or wasteful sacrificial reducing agents; otherwise, phenol yields are extremely low. Here we report a dual-catalysis non-noble metal system by simultaneously using graphitic carbon nitride (C₃N₄) and Keggin-type polyoxometalate H₅PMo₁₀V₂O ₄₀(PMoV₂) as catalysts, showing an exceptional activity for reductant-free aerobic oxidation of benzene to phenol. The dual-catalysis mechanism results in an unusual route to create phenol, in which benzene is activated on the melem unit of C₃N₄ and O₂ by the V-O-V structure of PMoV₂. This system is simple, highly efficient and thus may lead the one-step production of phenol from benzene to a more practical pathway.