Unlocking a High Photovoltage in BiVO 4 Photoanodes via Repairing Oxygen‐Defect‐Induced Surface Traps Boosting Photoelectrochemical Performance

ABSTRACT Oxygen vacancy‐rich bismuth vanadate (BiVO 4− x ) photoanodes usually exhibit excellent bulk charge separation efficiency and relatively low onset potential, but the Fermi‐level pinning effect leads to a relatively low photovoltage ( V ph ). Herein, we propose a synergistic strategy of F element doping and in situ deposition of the NiCoBi co‐catalyst to amplify the V ph of BiVO 4− x . Systematic investigations demonstrate that F doping modifies the electronic structure of BiVO 4− x , increases the electron work function, and synergizes with the NiCoBi co‐catalyst to repair surface defect states, thereby enhancing the V ph of the F‐BiVO 4− x /NiCoBi photoanode by 37.78% compared to its unmodified BiVO 4− x counterpart. Consequently, both organic oxidation reactions and water oxidation reactions are significantly activated. More importantly, the enhanced V p h can also improve the long‐term operational stability of the photoanode. Such improvements in multiple performance metrics can provide a universal strategy for the design of next‐generation photoelectrode materials.