Oxygen vacancies boosted Bi2WO6 for photoelectrochemical water oxidation

In this work, bismuth tungstate (Bi₂WO₆) films enriched with oxygen vacancies were fabricated via the hydrogen treatment with an excellent catalytic activity. The photocurrent density of Bi₂WO₆ H-15 is 0.18 mA/cm² at 1.23 V (vs. RHE), which is 11.25 times higher than that of pure Bi₂WO₆. The introduction of oxygen vacancy not only increases the charge concentration, facilitates the charge transport, promotes the water absorption ability, but also extends the light absorption of Bi₂WO₆. The density of states (DOS) calculated by the density functional theory (DFT) showed that a new defect level was formed and increased DOS at the valance band maximum (VBM). This work manifests the effective use of oxygen vacancies in regulating carriers transport, which is of great significance for the PEC oxygen evolution reaction.