Stable Cocatalyst‐Free BiVO4 Photoanodes with Passivated Surface States for Photocorrosion Inhibition

Improving charge transport and reducing bulk/surface recombination can increase the activity and stability of BiVO4 for water oxidation. Herein we demonstrate that the photoelectrochemical (PEC) performance of BiVO4 can be significantly improved by potentiostatic photopolarization. The resulting cocatalyst‐free BiVO4 photoanode exhibited a record‐high photocurrent of 4.60 mA cm−2 at 1.23 VRHE with an outstanding onset potential of 0.23 VRHE in borate buffer without a sacrificial agent under AM 1.5G illumination. The most striking characteristic was a strong “self‐healing” property of the photoanode, with photostability observed over 100 h under intermittent testing. The synergistic effects of the generated oxygen vacancies and the passivated surface states at the semiconductor–electrolyte interface as a result of potentiostatic photopolarization reduced the substantial carrier recombination and enhanced the water oxidation kinetics, further inhibiting photocorrosion. Potentiostatic photopolarization was induced on BiVO4 to improve charge transport, reduce interface recombination, and improve the water oxidation kinetics. The undoped BiVO4 photoanode exhibited a record‐high photocurrent of 4.60 mA cm−2 at 1.23 VRHE with an onset potential of 0.23 VRHE in borate buffer without a cocatalyst or a sacrificial agent. Strong “self‐healing” characteristics enabled photostability over 100 h under intermittent testing (see picture).