Enhanced photoelectrochemical water oxidation by WO3/BiVO4/Ti3C2/TiO2 photoanode

BiVO₄ is a promising semiconductor for photoelectrochemical water oxidation, yet its performance is still limited by rapid charge recombination and sluggish reaction kinetics. To address these challenges, a WO₃/BiVO₄/Ti₃C₂/TiO₂ photoanode is developed via the integration of the WO₃/BiVO₄ heterojunction with the Ti₃C₂/TiO₂ Schottky junction. This architecture establishes an internal electric field and cascaded charge transport pathway, collectively suppressing charge recombination. The carrier lifetime is extended to 3.112 ns compared to the WO₃/BiVO₄ heterojunction (2.111 ns). The hydrophilic nature of Ti₃C₂ facilitates charge transfer at the photoanode/electrolyte interface. Moreover, the optical absorption edge of the developed photoanode is extended, improving solar energy utilization. Because of these merits, the WO₃/BiVO₄/Ti₃C₂/TiO₂ photoanode yields a photocurrent density of 3.70 mA cm⁻² at 1.23 V vs. RHE, presenting an increase by 126 % over the WO₃/BiVO₄ photoanode. This work demonstrates a promising interfacial engineering approach to develop high-performance photoanodes.