W5+-W5+ Pair Induced LSPR of W18O49 to Sensitize ZnIn2S4 for Full-Spectrum Solar-Light-Driven Photocatalytic Hydrogen Evolution

The localized surface plasmon resonances (LSPR) effect makes W18O49 an effective visible and near-infrared (NIR) light antenna to realize full-spectrum solar-light driven photocatalysis, yet the precise origin remains elusive. Here, the LSPR originates from the localized electron confinement around lattice W5+-W5+ pairs in the unique structure of W18O49 by density-functional theory calculation, which gives W18O49 a broad absorption ranging from visible to NIR region, independent of the particle shape and size is confirmed. This unique periodic LSPR simplifies the design of W18O49-sensitized photocatalytic composite into enhancing the light absorbance of W18O49 and screening photocatalytic semiconductors with suitable energy band potentials. To this end, hierarchical-structure W18O49 microflowers with high absorbance have been coated with ZnIn2S4 nanosheets to achieve cocatalyst-free photocatalytic composite, which presents an outstanding H-2 production rate of 902.57 mu mol within 3 h under simulated solar-light. Comprehensive characterizations, including ultrafast transient absorption spectroscopy, prove the injection of hot electrons from W18O49 to ZnIn2S4 and the increase of long-lived active electrons. This work clarifies the LSPR origin of oxygen-deficient semiconductors and paves the way for the search of broad-spectrum active photocatalyst.