The use of semiconductor photocatalysts to generate electrons with efficient reducing capability for organic photoreduction synthesis and the removal of harmful substances has become a hotspot in the field of green chemistry research. In this work, α-MnO2 nanocubes and α-MnO2@MnIn2S4 hybrid photocatalysts with a core-shell structure were synthesized successively by a two-step method. XRD and XPS verified the coexistence of the two substances (α-MnO2 and MnIn2S4) in hybrid systems. According to the SEM and TEM characterization, it is clearly seen that MnIn2S4 nanosheets grow on α-MnO2 nanocubes to form a hierarchical structure. Furthermore, HRTEM showed that the interface contact between α-MnO2 and MnIn2S4 resulted in an atomically defined junction. The photocatalytic performance of the composite catalyst was evaluated by reducing 4-nitroaniline to 4-phenylenediamine and Cr(vi) to Cr(iii), respectively. The results show that the catalytic activity of the composite material is effectively improved compared to that of the single components. The Z-scheme electron transport mechanism was proved by ultraviolet-visible diffuse reflectance spectroscopy, valence band XPS, energy band structure calculation and active species detection experiments. The constructed Z-scheme hierarchical α-MnO2@MnIn2S4 system with an atomically defined junction can improve the redox performance of semiconductors for organic synthesis and environmental remediation.
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