Efficient photoelectrocatalytic performances using a WO/BiVO heterojunction photoanode: applied bias-promoted photoinduced charge transfer and separation.

Combining tungsten trioxide (WO) with bismuth vanadate (BiVO) to form a heterojunction photoanode offers a promising solution to achieving highly efficient photoelectrocatalytic (PEC) performances. In this work, we successfully fabricated the WO/BiVO heterojunction on tungsten (W) foil a hydrothermal route, followed by a successive ionic layer adsorption and reaction (SILAR) process. The PEC performances for synergetic H evolution and organic pollutant degradation were significantly enhanced after the BiVO nanoparticles were loaded on the WO photoanode. The PEC performance with the WO/BiVO heterojunction as the photoanode was demonstrated to be much more dependent on the applied bias potential () than that with pristine WO as the photoanode. Based on the various photoelectrochemical features and fundamental theory of semiconductor heterojunctions, it was well elucidated that, under the applied bias potential, the gradual diminishment and eventual reversal of the energy band bending at the heterojunction interface could achieve the efficient transfer and separation of more photogenerated charges, thereby enhancing overall PEC performances. This work highlights the roles of the evolution of the band bending in the WO/BiVO heterojunction interface by applied bias in promoting the efficient transfer and separation of photogenerated charges.