Dispersible CdSSe solid-solution nanocrystal photocatalysts: Photoinduced self-transformation synthesis and enhanced hydrogen-evolution activity.

Modulating the electronic structure of Cadmium sulfide (CdS) by non-metallic elements to produce solid-solution photocatalysts serves as a potential route to improve its performance of photocatalytic hydrogen (H) evolution. However, exploring an effective synthetic route of CdS-based solid solution is still a great challenge. Herein, the CdSSe solid-solution nanocrystals were successfully synthesized by an accessible photoinduced self-transformation route, including the direct formation of dispersible CdS(SeS) and the in situ self-transformation of selenosulfide ((SeS)) to Se by photoexcited electrons. The prepared CdSSe solid-solution photocatalysts possess a small crystallite size of ca. 5 nm and their bandgaps can be easily tuned in a wide range of 1.84-2.28 eV by tailoring the mole ratio of Se/S. The resultant CdSSe solid-solution photocatalyst realizes the highest H-production tempo of 94.6 μmol·h, which is 1.6 folds higher than that of CdS. The experimental and theoretical studies supported that the incorporation of Se atoms could not only narrow the bandgap value to reinforce visible-light absorption, but also tune its electronic structure to optimize interfacial H-evolution dynamics, thus achieving an efficient photocatalytic H-production rate of the dispersible CdSSe solid solution. This study may deliver advanced inspirations for optimizing the electronic structure of photocatalysts towards sustainable H production.