In Situ Construction of Fuzzy Sea‐Urchin ZnIn₂S₄/W₁₈O₄₉: Leveraging Interfacial Z‐Scheme Redox Sites toward Cooperative Electron–Hole Utilization in Photocatalysis

Abstract

Despite the significant milestones in the half‐reduction process of photocatalysis, challenges remain in fully utilizing electron–hole pairs in the simultaneous redox reactions. Herein, a Z‐scheme ZnIn2S4/W18O49 (ZW) hybrid with complementary band edge potential is in situ constructed. The resultant fuzzy 1D‐assembled sea‐urchin photocatalyst demonstrates an optimal H2 and benzaldehyde yield of 122 and 106 µmol h−1 under λ > 420 nm light irradiation. This sacrificial‐agent‐free system entails solar‐to‐hydrogen (STH) and apparent quantum efficiency (AQE) values of 0.466% and 2.48% (420 nm), respectively, surpassing most of the recently reported photocatalytic systems without the aid of noble metal cocatalysts. The outstanding performance is mainly attributed to the synergistic formation of intimate Z‐scheme heterojunction and the induction of localized surface plasmon resonances. Comprehensive characterization studies prove the direct injection of energetic hot electrons to promote the number of long‐lived active electrons. Besides, electron paramagnetic resonance and scavenger tests clarify the complicated mechanistic puzzle of the dual‐redox reaction, where benzaldehyde is formed dominantly via O─H activation followed by C─H cleavage of benzyl alcohol over ZW hybrid. Lastly, the universal use of the ZnIn2S4/W18O49 composites is testified in various dual‐redox systems. This study offers a novel outlook for designing dual‐functioning heterojunctions toward a feasible photoredox application.