W~(5+)–W~(5+) Pair Induced LSPR of W18O49 to Sensitize ZnIn2S4 for Full-Spectrum Solar-Light-Driven Photocatalytic Hydrogen Evolution

摘要

The localized surface plasmon resonances (LSPR) effect makes W_(18)O_(49) aneffective visible and near-infrared (NIR) light antenna to realize full-spectrumsolar-light driven photocatalysis, yet the precise origin remains elusive. Here,the LSPR originates from the localized electron confinement around latticeW~(5+)–W~(5+) pairs in the unique structure of W_(18)O_(49) by density-functional theorycalculation, which gives W_(18)O_(49) a broad absorption ranging from visible toNIR region, independent of the particle shape and size is confirmed. Thisunique periodic LSPR simplifies the design of W_(18)O_(49)-sensitized photocatalyticcomposite into enhancing the light absorbance of W_(18)O_(49) and screeningphotocatalytic semiconductors with suitable energy band potentials. To thisend, hierarchical-structure W_(18)O_(49) microflowers with high absorbance havebeen coated with ZnIn_2S_4 nanosheets to achieve cocatalyst-free photocatalyticcomposite, which presents an outstanding H_2 production rate of 902.57 μmolwithin 3 h under simulated solar-light. Comprehensive characterizations,including ultrafast transient absorption spectroscopy, prove the injection ofhot electrons from W_(18)O_(49) to ZnIn_2S_4 and the increase of long-lived activeelectrons. This work clarifies the LSPR origin of oxygen-deficient semiconductorsand paves the way for the search of broad-spectrum active photocatalyst.