C(3)N(4)-H(5)PMo(10)V(2)O(40): 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 O(2) 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 (C(3)N(4)) and Keggin-type polyoxometalate H(5)PMo(10)V(2)O(40) (PMoV(2)) 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 C(3)N(4) and O(2) by the V-O-V structure of PMoV(2). This system is simple, highly efficient and thus may lead the one-step production of phenol from benzene to a more practical pathway.