Constructing a 2D Heterointerface of MoS₂/MnIn₂S₄ with Improved Interfacial Charge Carrier Transfer for Photocatalytic H₂O₂ Production

Photocatalytic oxygen reduction to H2O2 is a promising sustainable solar fuel production pathway. Photocatalysts with heterostructure interfaces can suppress charge carrier recombination and endow photogenerated electrons and holes with improved redox potentials. This study develops a heterostructured two-dimensional (2D) MoS2/MnIn2S4 photocatalyst for photocatalytic H2O2 production. The photocatalyst with an optimal loading of MnIn2S4 on 2D MoS2 nanosheets demonstrates the maximum H2O2 production rate of 606.7 μmol g–1 h–1, approximately 4.2 and 5 times higher than pristine 2D MoS2 and MnIn2S4, respectively. The synergistic interaction between 2D MoS2 nanosheets and MnIn2S4 results in enhanced charge separation, optical absorption, stability, and recyclability. Reaction pathway studies reveal that H2O2 production is through a sequential single-electron O2 reduction reaction by accumulated photogenerated electrons on the conduction band of the 2D MoS2/MnIn2S4 heterostructure. This work presents a noble-metal-free photocatalyst responsive to visible light for solar H2O2 generation.