Efficient Solar Light Harvesting CdS/Co₉S₈ Hollow Cubes for Z‐Scheme Photocatalytic Water Splitting

Hollow structures with an efficient light harvesting and tunable interior component offer great advantages for constructing a Z‐scheme system. Controlled design of hollow cobalt sulfide (Co 9 S 8 ) cubes embedded with cadmium sulfide quantum dots (QDs) is described, using hollow Co(OH) 2 as the template and a one‐pot hydrothermal strategy. The hollow CdS/Co 9 S 8 cubes utilize multiple reflections of light in the cubic structure to achieve enhanced photocatalytic activity. Importantly, the photoexcited charge carriers can be effectively separated by the construction of a redox‐mediator‐free Z‐scheme system. The hydrogen evolution rate over hollow CdS/Co 9 S 8 is 134 and 9.1 times higher than that of pure hollow Co 9 S 8 and CdS QDs under simulated solar light irradiation, respectively. Moreover, this is the first report describing construction of a hollow Co 9 S 8 based Z‐scheme system for photocatalytic water splitting, which gives full play to the advantages of light‐harvesting and charges separation.