Engineering interface-mediated heterojunctions in MOF-derived C-In₂O₃ microrods and CdS nanoclusters for enhanced...

Photocatalytic H₂O₂ production is recognized as a promising route for addressing the energy crisis and environmental challenges. However, the photocatalysis efficiency is limited due to the poor charge separation and weak reaction kinetics of water oxidation during the processes of H₂O₂ production. In this work, we report the rational design of an interface-mediated CdS/C-In₂O₃ heterojunction for enhanced H₂O₂ production under visible light, which was synthesized from MOF-derived C-doped In₂O₃ (C-In₂O₃) and strategically integrated with CdS nanoclusters via a simple oil-bath process. The unique interfaces in C-In₂O₃ significantly increase the density of accessible active sites for the adsorption and activation of O₂. Furthermore, the engineered built-in electric field (BIEF) provided by the heterojunction is advantageous for achieving effective regulation of interfacial charge transfer and optimizing the two-step 1e^- reduction pathway (O₂ → ˙O₂^- → H₂O₂). Notably, the optimized CdS/C-In₂O₃ demonstrates a remarkably high photocatalytic H₂O₂ production rate of 2115 μmol g^-1 h^-1 and superior selectivity of 88.2%, which represents a 10.5-fold increase compared to bare C-In₂O₃. The mechanism of this highly efficient and robust photocatalytic system tailored for H₂O₂ production using a dual-modification strategy was attributed to the synergistic integration of morphology control, interface engineering and the heterojunction, which achieved enhanced surface area, promoted efficient charge transfer, and increased the adsorption and activation of O₂. This work offers valuable insights into the synergistic interplay of interface engineering and heterojunction for the design of In₂O₃-based photocatalysts with high efficiency and selective H₂O₂ production.