Direct Oxidation of Benzene to Phenol by Dioxygen over Nano‐vanadium Oxide

Abstract Reducing regents, such as ascorbic acid, are needed for vanadium‐containing catalysts to catalyze the direct oxidation of benzene to phenol by dioxygen. Quadrivalent vanadium species, reduced from quinquevalent vanadium species, can activate dioxygen to produce active oxygen species, which is important for the reaction. The key step is to prepare more V 4+ ‐containing catalysts. Here, VO X ‐C 16 ‐A was prepared in an acidic medium to produce more V 4+ species. The results of XPS and XRD studies confirmed that the vanadium species in VO X ‐C 16 ‐A was mainly V 4+ ions. The results of XRD and electron diffraction patterns revealed that VO X ‐C 16 ‐A consisted of tetragonal VO 2 and monoclinic VO 2 . Morphology observations display that the VO X ‐C 16 ‐A is made of nanorod. Investigations into the performances of the catalysts showed that VO X ‐C 16 ‐A was reusable, producing a 1.9% conversion of benzene without reducing agent.