Novel sandwich-shelled ZnCdS/ZnO/ZnCdS dodecahedral cages are synthesized with “one stone”, exhibiting advanced performance towards photocatalytic hydrogen production.

Semiconducting quantum dots (QDs) engineering is considered as an effective approach to improve the light-harvesting ability of the devices for solar energy converting. Current routes for the construction of QDs from metal–organic frameworks (MOFs) always retain carbon materials to avoid particle aggregations, which could obstruct light harvesting process. Herein, novel ZnCdS QDs without carbon supporting are rationally designed and fabricated by controlled annealing and a sequential sulfidation and ion-exchange procedure by a zeolitic-imidazolate-framework-8 (ZIF-8)-templated method. Notably, the quantum size could be well controlled, and hence provide the ZnCdS QDs material with suitable band matching, strong electron coupling, uniform and abundant active sites, facilitated photoinduced charge kinetics, and shortened charge diffusion distances, which are vital merits for enhancing photocatalytic performance. The photocatalytic H2 production activity of these QDs can be optimized through adjusting the quantum sizes. Under the irradiation of visible-light and noble-metal cocatalyst-free, an optimal H2 production rate of 3.70 mmol h–1 g–1 could be afford without using noble metal cocatalysts, which is superior to those of bulk ZnCdS and most of the reported ZnCdS-based catalysts. The facile and efficient approach for ZnCdS QDs engineering could be extended to design other kinds of highly efficient metal-sulfide QDs in advanced applications.

Using solar energy through green and simple artificial photosynthesis systems are considered as a promising way to solve the energy and environmental crisis. However, one of the important primary steps of photosynthesis, i.e., energy transfer, is long being ignored especially in inorganic semiconducting systems due to the small exciton binding energies. Herein, the simultaneous interrogation of the charge transfer and energy transfer steps in a photoexcitation process is proposed by utilizing few-layered nanosheet-assembled hierarchical BiOBr nanotubes with rich oxygen vacancies (OVs) as efficient multifunctional photocatalysts. Benefiting from the integrated 1D/2D structure and abundant OV defects, the excitonic effect strikes a delicate balance in the optimized BiOBr photocatalyst, showing not only improved charge carrier separation and transfer but also enhanced exciton generation. As a result, the hierarchical BiOBr nanotubes exhibit high efficiency toward photocatalytic CO 2 reduction with an impressive CO evolution rate of 135.6 µmol g −1 h −1 without cocatalyst or photosensitizer. The dominant reactive oxygen species of singlet oxygen ( 1 O 2 ) are discriminated for the first time, which originated from an energy transfer process, with electrophilic character, whereas the minor effect of superoxide anion radical ( • O 2 −) with a nucleophilic rate-determining step in the photocatalytic aerobic oxidation of sulfides.

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Low charge carrier mobility limits the development of highly efficient semiconductor-based photocatalysis. Heterointerface engineering is a promising approach to spatially separate the photoexcited charge carriers and thus enhance photocatalytic activity....