Tailoring the work function at Mott-Schottky junction enables efficient charge separation in Bi2WO6 photoanodes for enhanced photoelectrocatalytic water splitting

Photoelectrocatalytic water splitting represents a sustainable strategy for producing “green hydrogen” through visible-light-driven hydrogen evolution (HER) and oxygen evolution reactions (OER) under applied bias. The advancement of cost-effective photoelectrode materials with high efficiency and durability remains imperative, as single-component semiconductors often suffer from inadequate bandgap alignment, inefficient carrier separation, and insufficient stability. Herein, we fabricate Bi 2 WO 6 /Ti 3 C 2 T x -800 composite photoanodes on recyclable carbon felt (CF) substrates via electrophoretic deposition. By strategically modulating the work function at the Mott-Schottky junction of Bi 2 WO 6 /Ti 3 C 2 T x -800, we precisely tailored the energy band structure of Bi 2 WO 6 , enhancing its carrier separation efficiency and light absorption. The optimized system delivers a photocurrent density of 6.44 mA cm −2 at 1.23 V vs. reversible hydrogen electrode (RHE), alongside an applied bias photon-to-current efficiency (ABPE) of 0.73 % at 1.08 V and a charge-transfer efficiency (η tran ) of 74.68 % at 1.23 V, surpassing most reported Bi 2 WO 6 -based counterparts. This work establishes a robust design paradigm for high-performance photoanodes, advancing scalable solar-driven water-splitting technologies.