Single-Electron-Trapped Oxygen Vacancy on Ultrathin WO3•0.33H2O {100} Facets Suppressing Backward Reaction for Promoted H2 Evolution in Pure Water Splitting

Solar water splitting to produce hydrogen is a promising solution for global energy issues. One of the main bottlenecks in this technology is the spontaneous fast backward reaction (2H(2) + O-2 -> H2O, Delta G < 0), limiting the solar energy conversion efficiency. How to suppress backward reaction is vitally important but rarely reported. Here we found that single-electron-trapped oxygen vacancy (Vo center dot) can suppress spontaneous backward reaction in pure water splitting. Taking WO3 center dot 0.33H(2)O catalyst as an example, ultrathin WO3 center dot 0.33H(2)O {100} facets with large amount of surface Vo center dot realized a continuous H-2 evolution from pure water splitting with a productivity of 9.9 mu mol/g.h without the assistance of any sacrifice agent and noble metal cocatalyst. Quantum chemical calculations revealed that the backward-reaction suppression ability of Vo center dot is attributed to the high concentration of localized electrons around Vo center dot, stimulating unidirectional simultaneous water dissociation into H and OH under light irradiation.