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 H-2 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 H-2 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 H-2 evolution. Under optimal conditions, the Cu-0.4-ZnIn2S4 QDs could produce H-2 with the rate of 144.4 mu mol 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.

Automated summary

The study demonstrates that the photocatalytic H-2 evolution activity of quantized indium chalcogenide semiconductors can be significantly enhanced by the co-decoration of transition metals zinc and copper. Unlike traditional metal ion doping strategies, this new approach coordinates the regulation of conduction and valence bands to achieve bandgap narrowing and increasing thermodynamic driving force for proton reduction.