Facile hydrothermal synthesis of VO2 nanosheets as robust catalysts for liquid-phase selective oxidation of benzyl alcohol under atmospheric O2.

The liquid-phase selective oxidation of benzyl alcohol is a sustainable route for the synthesis of benzaldehyde. Wherein, the exploration of heterogeneous and cheap metal oxide catalysts instead of noble metal catalysts is of interest in both practical implementation and green chemistry. Herein, vanadium dioxide (VO2) nanosheets were prepared via a one-step hydrothermal reduction of V2O5 by citric acid. The hydrothermal temperature and time played important roles in determining the crystalline structure, morphology, and distribution of V valences of VO2 materials. In the selective oxidation of benzyl alcohol by atmospheric O2, VO2 materials as heterogeneous catalysts showed catalytic activity. Based on XPS and O2-TPD analysis, the catalytically active sites were proposed as V4+ species. At a reaction temperature of 95 °C, the maximum yield of benzaldehyde was up to 91.6% after 6 h, and the VO2-140-5 catalyst can be recycled at least five times without any obvious loss in activity. [ABSTRACT FROM AUTHOR]