Robust hollow tubular ZnIn2S4 modified with embedded metal-organic-framework-layers: Extraordinarily high photocatalytic hydrogen evolution activity under simulated and real sunlight irradiation

This work reported a facile one-step method for constructing hollow tubular ZnIn 2 S 4 modified by metal-organic-framework-layers (MOFL) with In-MOF as precursor to be efficient photocatalysts (ZnIn 2 S 4 -MOFL) for robust photocatalytic hydrogen evolution (PHE). The dominant catalyst of ZnIn 2 S 4 and cocatalytic role of MOFL synergistically promoted the separation of electron and hole pairs due to the direct Z-scheme photocatalytic system, leading to an extraordinarily high PHE activity. The density functional theory (DFT) results revealed the remarkably decreased density of states (DOS) of ZnIn 2 S 4 after coupling with the organic ligands of MOFL, indeed proving an effectively suppressed recombination of charge carriers and benefited the performance of photocatalytic reactions. Experimental PHE results showed that a large number of hydrogen bubbles were visible to naked eyes and the optimal hydrogen evolution reached 28.2 mmol/g/h, the highest value reported so far among ZnIn 2 S 4 -based photocatalysts, and almost 14.8 times higher than that of pristine ZnIn 2 S 4 . More importantly, the superior apparent quantum efficiencies (AQEs) of 22.67 % at monochromatic light (350 nm) and the stable hydrogen generation capability (5.7 mmol/g/h) under real sunlight irradiation all confirmed a promising catalyst of ZnIn 2 S 4 -MOFL for hydrogen evolution applications.