Medium-Entropy (FeCoNi)3S4 Cocatalysts With Excellent Photon Utilization, Carrier Dynamics, and Reaction Kinetics for Boosted Bifunctionally Photocatalytic Activity.

Medium-entropy compound with abundant surface sites, fast charge transport, and excellent chemical stability is recognized as a kind of promising cocatalyst or charge-transfer mediator. In this work, medium-entropy (FeCoNi)3S4 loaded ZnIn2S4 composites were synthesized by two-step solvothermal/water-bath reactions. The unique architectures combined photothermal effect with Schottky contact and charge-transfer "bridge", which markedly enhanced the photon utilization, beneficially improved the charge dynamics, and prominently optimized the redox kinetics. Encouragingly, the optimal catalyst achieved high hydrogen evolution and benzaldehyde generation rates of 40.9 and 40.6 mmol g-1 h-1, representing 34.1-fold and 40.6-fold enhancements over pure ZnIn2S4. Notably, the selectivity of benzaldehyde was as high as 94.59%, and a fantastic apparent quantum efficiency of 26.8% was entailed at 420 nm. This work may open up a promising method for exploring highly-efficient bifunctional photocatalytic systems.