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

BiVO 4 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 WO 3 /BiVO 4 /Ti 3 C 2 /TiO 2 photoanode is developed via the integration of the WO 3 /BiVO 4 heterojunction with the Ti 3 C 2 /TiO 2 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 WO 3 /BiVO 4 heterojunction (2.111 ns). The hydrophilic nature of Ti 3 C 2 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 WO 3 /BiVO 4 /Ti 3 C 2 /TiO 2 photoanode yields a photocurrent density of 3.70 mA cm −2 at 1.23 V vs. RHE, presenting an increase by 126 % over the WO 3 /BiVO 4 photoanode. This work demonstrates a promising interfacial engineering approach to develop high-performance photoanodes.