Dual-Ligand ZIF-8 Bearing the Cyano Group for Efficient and Selective Uranium Capture from Seawater.

Uranium extraction from seawater is a potential technique that will change the world. Adsorption capacity, selectivity, and antibacterial ability for high-performance uranium adsorbents remain the major challenges. In this study, a dual-ligand zeolitic imidazolate framework 8 (ZIF-8) decorated with cyano groups (ZIF-8-CN) is prepared via a facile blend strategy at room temperature. Owing to the abundant mesopores and nitrogen functional groups, ZIF-8-CN shows an extremely high uranium uptake of 1000 mg/g at pH = 6, which is 2.42 times that of pristine ZIF-8. Noteworthily, ZIF-8-CN possesses a 16.2 mg/g uranium adsorption in natural seawater within 28 days, and the distribution coefficient (Kd = 3.25 × 106 mL/g) is far greater than that for other coexisting metal ions, demonstrating a marked preference for uranyl ions. Except for the coordination between uranium and nitrogen in imidazole, the cyano groups provide additional adsorption sites and preferentially bind to uranyl, thereby strengthening the affinity for uranyl. Notably, ZIF-8-CN displays ultrastrong antimicrobial ability against both Escherichia coli and Staphylococcus aureus, which is greatly desired for the scale-up marine tests. Our study demonstrates the high potential of ZIF-8-CN in uranium capture and provides a wide scope for the application of mixed-ligand MOFs.

One-dimensional CdS@Cd0.5Zn0.5S@ZnS-Ni(OH)2 nano-hybrids with epitaxial heterointerfaces and spatially separated photo-redox sites enabling highly-efficient visible-light-driven H2 evolution.

Photocatalytic solar-to-fuel conversion has been of great interest in recent years. Nevertheless, the rational structural manipulation of photocatalysts toward an efficient H2 evolution reaction (HER) is still under-developed. In this work, by employing CdS nanowires as the growth substrate, unique one-dimensional (1D) CdS@Cd0.5Zn0.5S@ZnS-Ni(OH)2 heterostructures were first synthesized through the ultrasonic water-bath reaction combined with subsequent hydrothermal and in situ photo-deposition processes. Under the optimized conditions, CS@30CZ0.5S@40ZS-3N with 30 wt% Cd0.5Zn0.5S, 40 wt% ZnS, and 3 wt% Ni(OH)2 achieves a visible-light-driven HER activity as high as 86.79 mmol h-1 g-1 (corresponding to an apparent quantum yield of 22.8% at 420 nm), which is 4 and 119 times higher than that of Pt-decorated CS@30CZ0.5S@40ZS and CdS, respectively. In addition, CdS@Cd0.5Zn0.5S@ZnS-Ni(OH)2 is also endowed with a good stability for H2 production under long-term irradiation. The spatial separation of photo-redox sites and epitaxial heterointerfaces in CdS@Cd0.5Zn0.5S@ZnS-Ni(OH)2 nanowires facilitate the charge transfer and separation effectively, accounting well for their superior photocatalytic capability. The results indicated in this work could benefit the exploitation of high-performance nanostructures for promising photocatalytic applications.

Accelerated charge transfer of Cd0.5Zn0.5S@ZnS core-shell nano-spheres via decoration of Ni2P and g-C3N4 toward efficient visible-light-driven H2 production.

Development of noble-metal-free photocatalysts for efficient H2 production from sunlight-driven water-splitting has aroused great interest in recent years. Herein, unique Cd0.5Zn0.5S@ZnS core-shell nano-spheres decorated with Ni2P and g-C3N4 cocatalysts were prepared for the first time, and they are highly active and stable toward the visible-light-driven (λ > 420 nm) H2 evolution reaction (HER). Noticeably, the optimized Cd0.5Zn0.5S@ZnS-Ni2P/g-C3N4 with 50 wt% ZnS, 3 wt% Ni2P, and 8 wt% g-C3N4 (CZ0.5S@50ZS-3N/8CN) exhibits a superior HER activity of 55.43 mmol·g-1·h-1, approximately 25 and 18 times higher than those of CZ0.5S@50ZS and Pt-decorated CZ0.5S@50ZS (CZ0.5S@50ZS-Pt), respectively. Meanwhile, the corresponding apparent quantum yield (AQY) at 420 nm is as high as 21%. It is revealed that the protective ZnS shell on the CZ0.5S core enhances the photo-stability of the hybrid significantly. Moreover, the synergistic effect of the Ni2P and g-C3N4 cocatalysts leads to the effective transfer and separation of charge carriers. The results presented in this work may pave the way for the ingenious design and fabrication of highly active nano-structures for sufficient solar utilization.

Unique 1D Cd1- x Znx S@O-MoS2 /NiOx Nanohybrids: Highly Efficient Visible-Light-Driven Photocatalytic Hydrogen Evolution via Integrated Structural Regulation.

Development of noble-metal-free photocatalysts for highly efficient sunlight-driven water splitting is of great interest. Nevertheless, for the photocatalytic H2 evolution reaction (HER), the integrated regulation study on morphology, electronic band structures, and surface active sites of catalyst is still minimal up to now. Herein, well-defined 1D Cd1- x Znx S@O-MoS2 /NiOx hybrid nanostructures with enhanced activity and stability for photocatalytic HER are prepared. Interestingly, the band alignments, exposure of active sites, and interfacial charge separation of Cd1- x Znx S@O-MoS2 /NiOx are optimized by tuning the Zn-doping content as well as the growth of defect-rich O-MoS2 layer and NiOx nanoparticles, which endow the hybrids with excellent HER performances. Specifically, the visible-light-driven (>420 nm) HER activity of Cd1- x Znx S@O-MoS2 /NiOx with 15% Zn-doping and 0.2 wt% O-MoS2 (CZ0.15 S-0.2M-NiOx ) in lactic acid solution (66.08 mmol h-1 g-1 ) is about 25 times that of Pt loaded CZ0.15 S, which is further increased to 223.17 mmol h-1 g-1 when using Na2 S/Na2 SO3 as the sacrificial agent. Meanwhile, in Na2 S/Na2 SO3 solution, the CZ0.15 S-0.2M-NiOx sample demonstrates an apparent quantum yield of 64.1% at 420 nm and a good stability for HER under long-time illumination. The results presented in this work can be valuable inspirations for the exploitation of advanced materials for energy-related applications.