Hollow CoSe₂ nanocages derived from metal-organic frameworks as efficient non-precious metal co-catalysts for photocatalytic hydrogen production

Photocatalytic water splitting by semiconductor nanostructures is a challenging chemical process for harnessing abundant solar energy and obtaining clean H₂ fuel. To this end, photocatalysts that comprise efficient light-harvesting semiconductor nanostructures and noble metal-free robust co-catalysts have attracted considerable attention. In this study, we designed a noble metal-free nanohybrid consisting of CdS nanorods (NRs) as photoabsorbers and CoSe₂ nanocages as co-catalysts. Benefiting from suitable band edge potentials, abundant catalytically active sites, large surface area, and efficient photoexcited charge carrier transfer, the fabricated nanohybrid exhibited a remarkable photocatalytic H₂ evolution performance (82.5 mmol h^-1 g^-1), which is approximately 37.5 times higher than that of bare CdS NRs. Moreover, the observed H₂ evolution rate was even higher than those of even noble metal Pt-anchored CdS NR composites. Furthermore, the fabricated nanohybrid exhibited prominent recycling stability (50 h) under solar light irradiation. The key role of the co-catalyst, the effects of the catalyst dosage and scavenger concentration, and the origin of the photocatalytic H₂ production were comprehensively investigated. We believe that this design is the prospective path toward the development of three-dimensional hollow-type noble metal-free nanostructures for enhancing H₂ production.