MOF-Derived Hollow Tubular In₂O₃/M^IIIn₂S₄ (M^II: Ca, Mn, and Zn) Heterostructures: Synergetic Charge-Transfer Mechanism and Excellent Photocatalytic Performance to Boost Activation of Small Atmospheric Molecules

The rational design of hierarchical In2O3/MIIIn2S4 (MII: Ca, Mn, and Zn) hollow tubular (HT) heterostructures was successfully performed by the preferential growth of ternary metal sulfide (MIIIn2S4) two-dimensional (2D) nanosheets on MIL-68(In) metal–organic framework (MOF) derived hollow tubular In2O3 using a facile low-temperature reflux reaction. The efficiency of HT-In2O3/MIIIn2S4 binary heterojunctions was studied for the photocatalytic activation of small atmospheric molecules. The ultrafast interfacial charge migration, better photoexcited charge separation, and significantly improved photocatalytic H2, NH3, and H2O2 production could be attributed to the narrow band gap energy of the MIIIn2S4 and S-scheme electron migration mechanism between In2O3 and MIIIn2S4 components in the heterostructures. Thanks to its structural and compositional advantages, the optimal HT-In2O3/MIIIn2S4 (1:1) heterostructure photocatalysts exhibited outstanding photocatalytic hydrogen evolution reaction and nitrogen and oxygen reduction reaction activity under visible-light illumination. Among the HT-In2O3/MIIIn2S4 (1:1) hetrostructures, the HT-In2O3/ZnIn2S4 (1:1) photocatalyst displayed the highest H2, NH3, and H2O2 generation (5331, 870, and 5716 μmol g–1 h–1) with conversion efficiency of 34%, 6.5%, and 0.291%, respectively. This study offers a comprehensive analysis on how the coupling of three different d0, d5, and d10 ternary metal chalcogenides MIIIn2S4 with HT-In2O3 affects the photocatalytic H2, NH3, and H2O2 production.