Confinement of ultrasmall CoFe2O4 nanoparticles in hierarchical ZnIn2S4 microspheres with enhanced interfacial charge separation for photocatalytic H2 evolution

The charge carriers’ separation efficiency, light absorption capacity and microstructure of photocatalysts are important factors affecting the photocatalytic performance. Herein, we prepared the hierarchical ZnIn2S4 (ZIS) microspheres-confined CoFe2O4 nanoparticles (CFO NPs) p-n junction (CFO/ZIS) with enhanced charge carriers’ separation and extensive visible light response. Surprisingly, the 1% CFO/ZIS exhibits the optimal photocatalytic H2 evolution (PHE) activity, which is about over 3.7 times higher than pure ZIS. Furthermore, the apparent quantum yield (AQY) of the1% CFO/ZIS reaches 5.0% at 420 nm. In addition, the effects of various sacrificial reagent on the PHE were investigated in depth. And the formed photocatalytic reaction path of p-n junction effectively prevents the photocorrosion of ZIS. Hence, the photocatalytic activity and crystalline structure of 1% CFO/ZIS have no obvious change after five photocatalytic cycles, which shows that the photocatalyst possesses excellent chemical stability. Moreover, the as-prepared p-n junction shows outstanding photocatalytic performance for the degradation of 2-mercaptobenzothiazole (MBT). According to a series of experiments and characterizations, a possible photocatalytic mechanism for the CFO/ZIS p-n junction was proposed.