In-situ partial cation exchange-derived ZnIn2S4 nanoparticles hybridized 1D MIL-68/In2S3 microtubes for highly efficient visible-light induced photocatalytic H2 production

Herein, a ternary hollow heterostructure (MIL-68/In₂S₃/ZnIn₂S₄) has been designed and constructed through two-step in-situ growing procedures including the sulfurization of MIL-68(In) to produce MIL-68(In)/In₂S₃ (MIS) and partly Zn(II)-exchange of In(III) to produce ternary MIL-68/In₂S₃/ZnIn₂S₄ (MISZ). The thus fabricated ternary heterostructure inherit the microtube architecture of MIL-68(In) and the produced ZnIn₂S₄ (ZIS) nanoparticles were well anchored on MIS microtube. Because of the formation of close adjacent heterojunction, the resulting hierarchical hollow heterostructure MISZ would be beneficial to the visible-light induced photocatalytic hydrogen generation. The relative composition of the ternary components was controlled to find the best photocatalytic activities. Interestingly, being free of cocatalyst and using visible-light irradiation source, the optimized MISZ-15 photocatalyst manifest significant hydrogen evolution rate of 306.0 μmol g⁻¹ h⁻¹, which values are evidently higher than the results by binary MIS and pristine MIL-68(In). By integrating the photo-electrochemical and electron spin resonance (ESR) analyses, a plausible enhanced photocatalytic mechanism has been proposed in detail. Finally, the ternary MISZ heterostructure shows excellent stability and reusability, that provides a new route for constructing other MOF-based functional photocatalysts for efficient H₂ production under visible light irradiation.