Engineering oxygen vacancy on rutile TiO2 for efficient electron-hole separation and high solar-driven photocatalytic hydrogen evolution

Oxygen vacancy (V O ) plays a vital role in semiconductor photocatalysis. Rutile TiO 2 nanomaterials with controllable contents of V O (0–2.18%) are fabricated via an in situ solid-state chemical reduction strategy, with color from white to black. The bandgap of the resultant rutile TiO 2 is reduced from 3.0 to 2.56 eV, indicating the enhanced visible light absorption. The resultant rutile TiO 2 with optimal contents of V O (∼2.07%) exhibits a high solar-driven photocatalytic hydrogen production rate of 734 μmol h −1 , which is about four times as high as that of the pristine one (185 μmol h −1 ). The presence of V O elevates the apparent Fermi level of rutile TiO 2 and promotes the efficient electronhole separation obviously, which favor the escape of photogenerated electrons and prolong the life-time (7.6×10 3 ns) of photogenerated charge carriers, confirmed by scanning Kelvin probe microscopy, surface photovoltage spectroscopy and transient-state fluorescence. V O -mediated efficient photogenerated electron-hole separation strategy may provide new insight for fabricating other high-performance semiconductor oxide photocatalysts.