Dispersible CdS1−xSex solid-solution nanocrystal photocatalysts: Photoinduced self-transformation synthesis and enhanced hydrogen-evolution activity

Abstract

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 CdS1−xSex solid-solution nanocrystals were successfully synthesized by an accessible photoinduced self-transformation route, including the direct formation of dispersible CdS1−x(SeS)x and the in situ self-transformation of selenosulfide ((SeS)2−) to Se2− by photoexcited electrons. The prepared CdS1−xSex 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 CdS0.90Se0.10 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 CdS1−xSex solid solution. This study may deliver advanced inspirations for optimizing the electronic structure of photocatalysts towards sustainable H2 production.