Electrostatic Self-Assembly of CdS Quantum Dots with Co₉S₈ Hollow Nanotubes for Enhanced Visible Light Photocatalytic H₂ Production

CdS quantum dots (CdS QDs) are regarded as a promising photocatalyst due to their remarkable response to visible light and suitable placement of conduction bands and valence bands. However, the problem of photocorrosion severely restricts their application. Herein, the CdS QDs-Co₉S₈ hollow nanotube composite photocatalyst has been successfully prepared by loading Co₉S₈ nanotubes onto CdS QDs through an electrostatic self-assembly method. The experimental results show that the introduction of Co₉S₈ cocatalyst can form a stable structure with CdS QDs, and can effectively avoid the photocorrosion of CdS QDs. Compared with blank CdS QDs, the CdS QDs-Co₉S₈ composite exhibits obviously better photocatalytic hydrogen evolution performance. In particular, CdS QDs loaded with 30% Co₉S₈ (CdS QDs-30%Co₉S₈) demonstrate the best photocatalytic performance, and the H₂ production rate reaches 9642.7 μmol·g^-1·h^-1, which is 60.3 times that of the blank CdS QDs. A series of characterizations confirm that the growth of CdS QDs on Co₉S₈ nanotubes effectively facilitates the separation and migration of photogenerated carriers, thereby improving the photocatalytic hydrogen production properties of the composite. We expect that this work will facilitate the rational design of CdS-based photocatalysts, thereby enabling the development of more low-cost, high-efficiency and high-stability composites for photocatalysis.