BiVO₄/Bi₄V₂O₁₀ isometallic heterojunction coupled with FeOOH/NiOOH cocatalysts for efficient photoelectrochemical water oxidation

The four-electron water oxidation reaction in photoelectrochemical systems poses a major challenge to efficiently converting solar energy into chemical energy amid the global energy crisis. Herein, we report a strategy to develop a photoelectrochemical system using BiVO₄/Bi₄V₂O₁₀ isometallic heterojunction photoanodes paired with FeOOH/NiOOH cocatalysts to enhance water oxidation in neutral electrolytes. The results demonstrate that the BiVO₄/Bi₄V₂O₁₀/FeOOH/NiOOH photoanode achieves a photocurrent density of 4.48 mA/cm² at 1.23 V versus the reversible hydrogen electrode and an applied bias photon-to-current efficiency of 1.69 % at 0.63 V versus the reversible hydrogen electrode—significantly outperforming bare BiVO₄. This enhanced photoelectrochemical performance is attributed to the identical elemental composition and well-aligned energy band positions of Bi₄V₂O₁₀ and BiVO₄, which minimize charge recombination at the interface. Additionally, the FeOOH/NiOOH double-layer cocatalyst facilitates rapid transfer of photogenerated carriers, as confirmed by femtosecond transient absorption spectroscopy and transient photovoltage measurements. This approach provides a novel and effective pathway for advancing high-efficiency photoelectrochemical cells. © 2025 Elsevier Inc.