Simultaneous Conduction and Valence Band Regulation of Indium-Based Quantum Dots for Efficient H₂ Photogeneration

Indium-based chalcogenide semiconductors have been served as the promising candidates for solar H₂ evolution reaction, however, the related studies are still in its infancy and the enhancement of efficiency remains a grand challenge. Here, we report that the photocatalytic H₂ evolution activity of quantized indium chalcogenide semiconductors could be dramatically aroused by the co-decoration of transition metal Zn and Cu. Different from the traditional metal ion doping strategies which only focus on narrowing bandgap for robust visible light harvesting, the conduction and valence band are coordinately regulated to realize the bandgap narrowing and the raising of thermodynamic driving force for proton reduction, simultaneously. Therefore, the as-prepared noble metal-free Cu_0.4-ZnIn₂S₄ quantum dots (QDs) exhibits extraordinary activity for photocatalytic H₂ evolution. Under optimal conditions, the Cu_0.4-ZnIn₂S₄ QDs could produce H₂ with the rate of 144.4 μmol h^-1 mg^-1, 480-fold and 6-fold higher than that of pristine In₂S₃ QDs and Cu-doped In₂S₃ QDs counterparts respectively, which is even comparable with the state-of-the-art cadmium chalcogenides QDs.