Nanoconfined Nickel@Carbon Core–Shell Cocatalyst Promoting Highly Efficient Visible‐Light Photocatalytic H2 Production

The realization of large‐scale solar hydrogen (H₂) production relies on the development of high‐performance and low‐cost photocatalysts driven by sunlight. Recently, cocatalysts have demonstrated immense potential in enhancing the activity and stability of photocatalysts. Hence, the rational design of highly active and inexpensive cocatalysts is of great significance. Here, a facile method is reported to synthesize Ni@C core–shell nanoparticles as a highly active cocatalyst. After merging Ni@C cocatalyst with CdS nanorod (NR), a tremendously enhanced visible‐light photocatalytic H₂‐production performance of 76.1 mmol g^?1 h^?1 is achieved, accompanied with an outstanding quantum efficiency of 31.2% at 420 nm. The state‐of‐art characterizations (e.g., synchrotron‐based X‐ray absorption near edge structure) and theoretical calculations strongly support the presence of pronounced nanoconfinement effect in Ni@C core–shell nanoparticles, which leads to controlled Ni core size, intimate interfacial contact and rapid charge transfer, optimized electronic structure, and protection against chemical corrosion. Hence, the combination of nanoconfined Ni@C with CdS nanorod leads to significantly improved photocatalytic activity and stability. This work not only for the first time demonstrates the great potential of using highly active and inexpensive Ni@C core–shell structure to replace expensive Pt in photocatalysis but also opens new avenues for synthesizing cocatalyst/photocatalyst hybridized systems with excellent performance by introducing nanoconfinement effect.     

Enhanced Vertical Charge Transport of Homo- and Blended Semiconducting Polymers by Nanoconfinement

The morphology of conjugated polymers has critical influences on electronic and optical properties of optoelectronic devices. Even though lots of techniques and methods are suggested to control the morphology of polymers, very few studies have been performed inducing high charge transport along out-of-plane direction. In this study, the self-assembly of homo- and blended conjugated polymers which are confined in nanostructures is utilized. The resulting structures lead to high charge mobility along vertical direction for both homo- and blended conjugated polymers. Both semicrystalline and amorphous polymers show highly increased population of face-on crystallite despite intrinsic crystallinity of polymers. They result in more than two orders of magnitude enhanced charge mobility along vertical direction revealed by nanoscale conductive scanning force microscopy and macroscale IV characteristic measurements. Moreover, blends of semicrystalline and amorphous polymers, which are known to show inferior optical and electrical properties due to their structural incompatibility, are formed into harmonious states by this approach. Assembly of blends of semicrystalline and amorphous polymers under nanoconfinement shows charge mobility in out-of-plane direction of 0.73 cm² V⁻¹ s⁻¹ with wide range of absorption wavelength from 300 to 750 nm demonstrating the synergistic effects of two different polymers.     

A Scalable Nickel–Cellulose Hybrid Metamaterial with Broadband Light Absorption for Efficient Solar Distillation

Sophisticated metastructures are usually required to broaden the inherently narrowband plasmonic absorption of light for applications such as solar desalination, photodetection, and thermoelectrics. Here, nonresonant nickel nanoparticles (diameters < 20 nm) are embedded into cellulose microfibers via a nanoconfinement effect, producing an intrinsically broadband metamaterial with 97.1% solar-weighted absorption. Interband transitions rather than plasmonic resonance dominate the optical absorption throughout the solar spectrum due to a high density of electronic states near the Fermi level of nickel. Field solar purification of sewage and seawater based on the metamaterial demonstrates high solar-to-water efficiencies of 47.9–65.8%. More importantly, the solution-processed metamaterial is mass-producible (1.8 × 0.3 m²), low-cost, flexible, and durable (even effective after 7 h boiling in water), which are critical to the commercialization of portable solar-desalination and domestic-water-purification devices. This work also broadens material choices beyond plasmonic metals for the light absorption in photothermal and photocatalytic applications.     

纳米限域材料的制备及其在污染治理中的应用研究进展

纳米技术在环境污染治理中具有广泛前景,然而其在应用过程中存在纳米颗粒及活性中心易团聚失活的问题。将纳米粒子的活性中心限制在载体的孔道内,构建出新型纳米限域材料可以有效克服这一缺点。同时,凭借材料的纳米限域效应,一定程度上可影响水的氢键网络结构,并会影响反应中中间活性粒子的演化、传质速率、晶体的生长和成核阶段过程,以及提高局部空间内反应底物的浓度。本文系统梳理了纳米限域材料的制备方法,并对比分析了各种制备方法的优缺点,归纳总结了近年来纳米限域材料在吸附和高级氧化降解污染物中的研究进展,展望了未来纳米限域材料在环境污染物治理领域的研发及应用前景。     

Nanosilica‐Confined Synthesis of Orthogonally Active Catalytic Metal Nanocrystals in the Compartmentalized Carbon Framework

Multifunctionalized porous catalytic nanoarchitectures are highly desirable for a variety of chemical transformations; however, selective installation of different catalysts with spatial and functional precision working synergistically and predictably, is highly challenging. Here, a synthetic strategy is developed toward the customizable combination of orthogonally reactive metal nanocrystals within interconnected carbon‐cavities as a compartmentalized framework by employing aminated‐silica‐directed thermal solid‐state nanoconfined synthesis of metal nanocrystals and endotemplating concomitant carbonization‐mediated interlocking, as key processes. The main advantage of the strategy is the facility to choose any combination of metals, which can be further employed according to the desired application. The strategically synthesized compartmentalized multifunctional catalytic architectures of Pd‐Pt@Com‐CF regulate the O₂‐mediated selective cascade oxidation reaction converting alcohol to acid with high yield and selectivity; and another Pt‐Ir@Com‐CF platform is demonstrated as a bifunctional electrocatalyst for oxygen reduction/evolution reactions.     

Solvation-Involved Nanoionics: New Opportunities from 2D Nanomaterial Laminar Membranes

Nanoporous laminar membranes composed of multilayered 2D nanomaterials (2D-NLMs) are increasingly being exploited as a unique material platform for understanding solvated ion transport under nanoconfinement and exploring novel nanoionics-related applications, such as ion sieving, energy storage and harvesting, and in other new ionic devices. Here, the fundamentals of solvation-involved nanoionics in terms of ionic interactions and their effect on ionic transport behaviors are discussed. This is followed by a summary of key requirements for materials that are being used for solvation-involved nanoionics research, culminating in a demonstration of unique features of 2D-NLMs. Selected examples of using 2D-NLMs to address the key scientific problems related to nanoconfined ion transport and storage are then presented to demonstrate their enormous potential and capabilities for nanoionics research and applications. To conclude, a personal perspective on the challenges and opportunities in this emerging field is presented.     

In Situ Grown Epitaxial Heterojunction Exhibits High‐Performance Electrocatalytic Water Splitting

Electrocatalytic performance can be enhanced by engineering a purposely designed nanoheterojunction and fine‐tuning the interface electronic structure. Herein a new approach of developing atomic epitaxial in‐growth in Co‐Ni₃N nanowires array is devised, where a nanoconfinement effect is reinforced at the interface. The Co‐Ni₃N heterostructure array is formed by thermal annealing NiCo₂O₄ precursor nanowires under an optimized condition, during which the nanowire morphology is retained. The epitaxial in‐growth structure of Co‐Ni₃N at nanometer scale facilitates the electron transfer between the two different domains at the epitaxial interface, leading to a significant enhancement in catalytic activities for both hydrogen and oxygen evolution reactions (10 and 16 times higher in the respective turn‐over frequency compared to Ni₃N‐alone nanorods). The interface transfer effect is verified by electronic binding energy shift and density functional theory (DFT) calculations. This nanoconfinement effect occurring during in situ atomic epitaxial in‐growth of the two compatible materials shows an effective pathway toward high‐performance electrocatalysis and energy storages.     

Nanoconfined LiBH4 as a Fast Lithium Ion Conductor

Designing new functional materials is crucial for the development of efficient energy storage and conversion devices such as all solid‐state batteries. LiBH₄ is a promising solid electrolyte for Li‐ion batteries. It displays high lithium mobility, although only above 110 °C at which a transition to a high temperature hexagonal structure occurs. Herein, it is shown that confining LiBH₄ in the pores of ordered mesoporous silica scaffolds leads to high Li⁺ conductivity (0.1 mS cm^?1) at room temperature. This is a surprisingly high value, especially given that the nanocomposites comprise 42 vol% of SiO₂. Solid state ⁷Li NMR confirmed that the high conductivity can be attributed to a very high Li⁺ mobility in the solid phase at room temperature. Confinement of LiBH₄ in the pores leads also to a lower solid‐solid phase transition temperature than for bulk LiBH₄. However, the high ionic mobility is associated with a fraction of the confined borohydride that shows no phase transition, and most likely located close to the interface with the SiO₂ pore walls. These results point to a new strategy to design low‐temperature ion conducting solids for application in all solid‐state lithium ion batteries, which could enable safe use of Li‐metal anodes.     

Magnetic Metal–Organic Frameworks: γ‐Fe2O3@MOFs via Confined In Situ Pyrolysis Method for Drug Delivery

A general one‐step in situ pyrolysis route for the construction of metal–organic frameworks encapsulating superparamagnetic γ‐Fe₂O₃ NPs dispersed in the confined cavities of MOFs homogeneously is described. The integration of γ‐Fe₂O₃ NPs or clusters into MOFs can endow these porous materials with superparamagnetic element. By the combination of the thermal stability of MOFs and pyrolysis of metal triacetylacetonate complex at matched conditions, the porous structure of MOFs are well maintained while the size‐induced superparamagnetic property of nano γ‐Fe₂O₃ is obtained. As a proof of concept, both the γ‐ Fe₂O₃@ZIF‐8 and γ‐Fe₂O₃@MIL‐53(Al) were successfully prepared, and the latter was chosen to demonstrate its potential drug delivery as a magnetic MOF.