A novel 2D/1D core-shell heterostructures coupling MOF-derived iron oxides with ZnIn2S4 for enhanced photocatalytic activity

1D spindle-like iron oxides with controllable phase were synthesized by using MIL-88A-templated pyrolysis under different atmospheres, thermal annealing in N2 to obtain Fe3O4 and in air to obtain α-Fe2O3. Then, 2D/1D core-shell heterostructures (ZnIn2S4@Fe3O4 and ZnIn2S4@α-Fe2O3) were constructed by in-situ self-assembly strategy. Characterizations indicated that the 2D ultra-thin ZnIn2S4 shell with 0.3 μm was homogeneously coated on the surface of 1D Fe3O4/α-Fe2O3 core with 1 μm, and ZnIn2S4@Fe3O4 exhibited higher BET surface area (84.5 m2 g−1) compared with ZnIn2S4@α-Fe2O3 (17.8 m2 g−1), providing more exposed active sites and larger contact area. The ZnIn2S4@Fe3O4-5 showed the best photocatalytic activity of RhB degradation as compared to ZnIn2S4, Fe3O4 and ZnIn2S4@α-Fe2O3. In addition, the degradation rates of MB, BPA and MO over ZnIn2S4@Fe3O4 were much higher than that of ZnIn2S4@α-Fe2O3. The proposed photocatalytic mechanism was also discussed: the Fe3O4 as an electron acceptor caused Fe3+/Fe2+ cycle in ZnIn2S4@Fe3O4 and ZnIn2S4@α-Fe2O3 followed the Z-scheme mechanism.