Tungsten induced defects control on BiVO4 photoanodes for enhanced solar water splitting performance and photocorrosion resistance

Abstract The stabilization of semiconductor against photocorrosion has become one of the most essential targets in photoelectrochemical water splitting. Herein, a research of three mixing enhancement strategies of WO3/BiVO4 heterojunction, W doping, and oxygen vacancy formation can be made to incorporate into such a nanostructure during the preparation of BiVO4 in terms of PEC performance improvement. The WO3 layer not only facilitated the electron transfer, but importantly, was used as a diffusion source for W doping which brought oxygen vacancies on the bulk material. Moreover, the introduction of different W doping profiles,- bottom, middle, and top, all electrodes exhibited a photo-activation character with the improved photocurrent and the negative shift of onset potential. The bottom W doping led to the most notable enhancement in charge separation efficiency on BiVO4 electrode, which yielded the close photocurrent densities of ∼4.4 mA cm−2 at 1.23 VRHE under front and back 1 sun illumination. More importantly, the cocatalyst-free W:BiVO4-Ov photoanode present a favorable stability during 25 h test applied at 1.0 VRHE. By experimental and theoretical arguments, it demonstrated that the multiple collaborative strategies shed light on designing efficient and stable photoelectrodes for solar energy conversion.