Photocatalytic production of hydrogen by vanadium oxides under visible light irradiation

Hydrogen has long been regarded as one of promising candidates for a new energy carrier. In particular, water-splitting by photoelectrolysis was verified to be a unique route for hydrogen production, since there are the abundance of the water and light around the world. Semiconductor metal oxides such as TiO2, Ta3N5, and Ag3VO4 are often treated as the photocatalysts for light-induced photo-oxidation of water. In this work, various kinds of vanadium oxides, V6O13, VO2(B), VO2(M), and V2O5 were examined their activity of hydrogen-production. From the results of cyclic voltammogram and the UV–vis spectra, the potential band structure for each sample was constructed. As a consequence, the relative NHE potential was achieved, and all the vanadium oxides prepared in this study were qualified as the visible-light-responsive photocatalysts for hydrogen production. The accumulative amount of hydrogen-production within 4 h illumination increased in the order of V6O13 > VO2(M) > V2O5 > VO2(B).