Hollow Co₉S₈/CdS Nanocages as Efficient Photocatalysts for Hydrogen Evolution

Abstract

The development of highly efficient photocatalysts is the key for the application of hydrogen production. Due to the narrow band gap and high catalytic activity, Co9S8 is considered as a prospective photocatalyst for hydrogen evolution from water splitting. Nevertheless, the serious recombination of carriers on Co9S8 always results in an ultrapoor performance on hydrogen evolution. Herein, we combine CdS quantum dots on hollow dodecahedron Co9S8 to form heterostructured Co9S8/CdS nanocages by a low-energy atmospheric one-pot strategy. Owing to the Z-type heterojunction, the hollow structure, size effect of quantum dots, and abundant active sites, the separation and migration of carriers are accelerated, and the electron–hole recombination is successfully suppressed. The catalyst hollow Co9S8/CdS nanocages show a remarkable activity with the hydrogen production efficiency of 14963 μmol·h–1·g–1, which is 5.7 and 28.5 times as high as those of pure CdS and Co9S8, respectively. Besides, the long-term (up to 30 h) stability also indicates that the photocatalyst hollow Co9S8/CdS nanocages have a great potential in the photocatalytic splitting of water for hydrogen evolution.

Polycrystalline CoO−Co9S8 Heterostructure Nanoneedle Arrays as Bifunctional Catalysts for Efficient Overall Water Splitting

“…[31] Significantly, the Co 2 + À S and Co 3 + À S peaks shift toward a lower binding energy compared to Co 9 S 8 , while the Co 2 + À O peaks shift to a higher binding energy, indicating the electrons transfer from Co 3 + /Co 2 + in Co 9 S 8 to Co 2 + in CoO. [32] Similarly, the above results are supported by S 2p and O 1s spectra. The negative shift in lattice oxygen peak and the positive shifts in S 2p peaks further indicate that the electrons transfer from Co sites in Co 9 S 8 to Co sites in CoO via the CoÀ S and CoÀ O bonds at the interface.…”

Cadmium Chalcogenide (CdS, CdSe, CdTe) Quantum Dots for Solar‐to‐Fuel Conversion

“…Finally, CdS QDs are successfully prepared. [32] QDs obtained by this approach usually have good dispersibility, high purity, and high crystallinity. Moreover, the particle size, crystallinity, surface stoichiometry, and capping reagents of the QDs can be tuned by precisely controlling the reaction parameters.…”

Recent advances in solution assisted synthesis of transition metal chalcogenides for photo-electrocatalytic hydrogen evolution

“…For instance, Co 9 S 8 is mainly formed through sulfidation of a ZIF-67 framework. [124][125][126] In the synthesis, ZIF-67 was synthesized first by simply mixing and aging solutions of cobalt nitrate and 2-methylimidazole. Sulfidation of ZIF-67 was carried out through a solvothermal process in the presence of sulfur reagents (thiocetamide, thiourea and L-cysteine).…”