Construction of a novel electron transfer pathway by modifying ZnIn2S4 with α-MnO2 and Ag for promoting solar H2 generation

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Using photocatalysts to split water by solar energy for sustainable H2 generation has aroused researchers' wide concern. In this study, we chose α-MnO2 as the electron storage and transfer medium, and introduced the surface plasma resonance effect of Ag into the composite material to successfully prepare novel ternary Ag/α-MnO2/ZnIn2S4 (Ag/α-MnO2/ZIS) photocatalysts. Various technologies such as photoluminescence (PL), Photocurrent-Time (PC), Linear sweep voltammetry (LSV), Mott–Schottky measurement (M–S) and electrochemical impedance spectra (EIS) were used to characterize the ternary Ag/α-MnO2/ZnIn2S4 photocatalysts. Noteworthy, due to the synergistic effect of the three materials, the composite catalysts have the characteristics of excellent optical properties, more active sites, greater carrier density, and stronger carrier separation and transfer ability. This structural design can remarkably improve photocatalytic performance driven by visible light. As expected, the Ag/α-MnO2/ZnIn2S4 photocatalysts exhibit excellent photocatalytic activity with a maximum H2-production rate of 3.65 mmol g-1 h−1, and it is about 14.9 times higher than that of pure ZnIn2S4. Furthermore, the ternary Ag/α-MnO2/ZnIn2S4 photocatalysts show recycle ability and good stability, and a photogenerated electron transfer mechanism has been put forward and detailly analyzed. The work offers a novel strategy to design highly active visible light photocatalysts for clean energy.