Spatially Separating Redox Centers and Photothermal Effect Synergistically Boosting the Photocatalytic Hydrogen Evolution of ZnIn2S4 Nanosheets

Spatially separated loading of reductive and oxidative cocatalysts is a useful strategy for expediting charge separation and surface reaction kinetics, which are two key factors for determining the photocatalytic efficiency. However, loading the spatial separation of dual cocatalysts on a 2D photocatalyst is still a great challenge. Herein, decorating the spatial separation of oxidative and reductive cocatalysts on ZnIn2S4 nanosheets is realized by designing a ternary Co9S8@ZnIn2S4@PdS (CS@ZIS@PS) hollow tubular core-shell structure. Particularly, Co9S8 and PdS functionally serve as the reduction and oxidation cocatalysts, respectively. Experimental results confirm that the spatial separation of Co9S8 and PdS cocatalysts not only efficiently improve charge separation and accelerate surface reduction-oxidation kinetics, but also generate a photothermal effect to further enhance charge transfer and surface reaction kinetics. As a result, the optimized CS@ZIS@PS yields a remarkable H-2 evolution rate of 11407 mu mol g(-1) h(-1), and the apparent quantum efficiency reaches 71.2% at 420 nm, which is one of the highest values among ZnIn2S4 so far. The synergistic effect of spatially separated dual cocatalysts and photothermal effect may be applied to other 2D materials for efficient solar energy conversion.

Automated summary

Spatially separated loading of reductive and oxidative cocatalysts on ZnIn2S4 nanosheets was achieved through designing a ternary Co9S8@ZnIn2S4@PdS (CS@ZIS@PS) hollow tubular core-shell structure. This structure not only efficiently improved charge separation and accelerated surface reduction-oxidation kinetics, but also generated a photothermal effect to further enhance charge transfer and surface reaction kinetics. The optimized CS@ZIS@PS showed a remarkable H-2 evolution rate and apparent quantum efficiency, making it one of the highest values among ZnIn2S4 materials.