A localized surface plasmon resonance effect boosts photocatalytic hydrogen evolution of ZnIn2S4/amorphous MoO3−x nanodot Z-scheme heterojunctions

Abstract

Plasmonic photocatalysts have attracted considerable attention in photocatalytic systems. In this study, amorphous molybdenum oxide (MoO_3−x) nanodots were anchored onto ZnIn₂S₄ nanospheres by a hydrothermal method. The prepared ZnIn₂S₄/MoO_3−x (ZM) composites were then used as a visible-light-responsive catalyst to achieve photocatalytic hydrogen evolution. Afterwards, the ZM composites were extensively characterized using multiple instruments and electrochemical measurements. Afterwards, the photocatalytic activity of ZM composites was evaluated under simulated sunlight (AM 1.5G) with 10% triethanolamine (TEOA) as a sacrificial reagent. Compared to pristine ZnIn₂S₄, the optimal composite (ZM10) boosts the hydrogen evolution rate from 1.34 mmol g⁻¹ h⁻¹ to 11.08 mmol g⁻¹ h⁻¹ and the apparent quantum efficiency (AQE) at 420 nm from 1.81% to 6.14%. The mechanism behind the enhanced photocatalytic hydrogen evolution was explored by infrared thermal image measurement, EPR tests, XPS valence band measurement and density functional theory (DFT) calculations. The localized surface plasmon resonance (LSPR) effect of MoO_3−x and the formation of an interfacial Z-scheme heterojunction are revealed to be responsible for the improved photocatalytic hydrogen evolution. Finally, the cyclic experiment results show that ZM10 maintains a high hydrogen evolution rate after 5 cycles of testing, indicating strong chemical stability and good industrial potential.