Dispersible CdS_1-xSe_x solid-solution nanocrystal photocatalysts: Photoinduced self-transformation synthesis and...

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 (H₂) evolution. However, exploring an effective synthetic route of CdS-based solid solution is still a great challenge. Herein, the CdS_1-xSe_x solid-solution nanocrystals were successfully synthesized by an accessible photoinduced self-transformation route, including the direct formation of dispersible CdS_1-x(SeS)_x and the in situ self-transformation of selenosulfide ((SeS)^2-) to Se^2- by photoexcited electrons. The prepared CdS_1-xSe_x 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 CdS_0.90Se_0.10 solid-solution photocatalyst realizes the highest H₂-production tempo of 94.6 μmol·h^-1, 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 H₂-evolution dynamics, thus achieving an efficient photocatalytic H₂-production rate of the dispersible CdS_1-xSe_x solid solution. This study may deliver advanced inspirations for optimizing the electronic structure of photocatalysts towards sustainable H₂ production.