Oxygen Vacancy Mediated Plasmonic Bi 2 S 3 /W 18 O 49 S‐Scheme Heterojunction for Efficient Hydrogen Evolution

ABSTRACT Solar‐driven hydrogen production requires photocatalysts with broad‐spectrum light harvesting and efficient charge separation. Herein, a plasmonic Bi 2 S 3 /W 18 O 49 S‐scheme heterojunction was constructed via a one‐pot solvothermal strategy, with W 18 O 49 nanowires grown in situ on Bi 2 S 3 nanorods. Aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy directly revealed oxygen‐vacancy‐induced lattice distortion in W 18 O 49 , providing atomic‐scale evidence of defect formation. Oxygen vacancies endow W 18 O 49 with enhanced localized surface plasmon resonance (LSPR) effect, extending near‐infrared absorption and improving solar utilization. The optimized heterojunction achieves an apparent quantum yield of 10.1% at 420 nm for photocatalytic H 2 evolution. Ultraviolet photoelectron spectroscopy, Mott‐Schottky, and femtosecond transient absorption analyses confirm an efficient S‐scheme charge‐transfer pathway driven by the interfacial electric field, enabling directional carrier migration while preserving strong redox capability. This work highlights the dual role of oxygen vacancies in plasmonic light harvesting and interfacial charge transfer for efficient solar hydrogen production.