Enhanced Photoelectrochemical Performance of BiVO4 Photoanodes Through Few-Layer MoS2 Composite Formation for Efficient Water Oxidation

Abstract

Photoelectrochemical water splitting (PEC-WS) provides a sustainable route to transform solar energy into hydrogen; however, its overall efficiency is constrained by the inherently slow kinetics of the oxygen evolution reaction. Bismuth vanadate (BiVO4) is considered an attractive visible-light-responsive photoanode due to its suitable band gap (similar to 2.4 eV) and chemical stability; however, its efficiency is restricted by limited charge transport and significant charge carrier recombination. To overcome these limitations, BiVO4-MoS2 (BVO-MS) heterostructures were synthesized through a simple in situ hydrothermal approach, ensuring robust interfacial coupling and uniform dispersion of MS nanosheets over BVO dendritic surfaces. This intimate contact promotes rapid charge transfer and improved light-harvesting capability. Structural and spectroscopic analyses confirmed the formation of monoclinic BVO with uniformly integrated amorphous MS. The optimized BVO-MS10 electrode delivered a photocurrent density of 4.72 mA cm(-2) at 0.6 V vs. SCE, approximately 5.3 times higher than pristine BVO, and achieved an applied bias photon-to-current efficiency of 0.49%. Mott-Schottky analysis revealed a distinct negative shift in the flat-band potential for BVO-MS10, indicative of an upward movement of its conduction band and the establishment of a strong internal electric field that enhances charge separation and interfacial electron transport. These synergistic effects collectively endow the in situ engineered BVO-MS heterostructure with superior PEC water oxidation performance and highlight its promise for efficient solar-driven hydrogen generation.