Spatially Confined Construction of Ultrasmall Pd Clusters Within Nitro-Bonded Covalent Organic Frameworks for Efficient Alkyne Semihydrogenation.

Confinement of metal species in porous supports is an effective strategy to optimize hydrogenation performance ascribing to tunable nanopore environments. However, only focusing on the electronic structure modulation for metal species has limited the design of improved catalysts. Herein, spatial confinement strategy is reported for constructing ultrasmall metal clusters in nitro-bonded COF (M@TpPa-NO, M = Pd, Pt, Ru, Rh, Ir).

Photocatalytic Extraction of Uranium from Seawater Using Covalent Organic Framework Nanowires.

In the push to achieve net-zero emissions by 2050, nuclear power will play an essential role alongside renewable wind and solar power, and correspondingly global interest and investment in this well-established technology is accelerating. The uranium present in seawater could support nuclear power generation for centuries, but traditional adsorptive separation strategies have proven ineffective for the selective extraction of uranium from this vast resource. Here, we report the synthesis of nanowires of a triazine-linked two-dimensional covalent organic framework via a solvent modulation approach, which can be used to access nanowire external diameters ranging from 50 to 200 nm.

Heterovalent Metal Pair Sites on Metal-Organic Framework Ordered Macropores for Multimolecular Co-Activation.

The precise design of catalytic metal centers with multiple chemical states to facilitate sophisticated reactions involving multimolecular activation is highly desirable but challenging. Herein, we report an ordered macroporous catalyst with heterovalent metal pair (HMP) sites comprising Cu-Cu on the basis of a microporous metal-organic framework (MOF) system. This macroporous HMP catalyst with proximity heterovalent dual copper sites, whose distance is controlled to ∼2.

Non-planar Nest-like [Fe S ] Cluster Sites for Efficient Oxygen Reduction Catalysis.

Metal-nitrogen-carbon catalysts, as promising alternative to platinum-based catalysts for oxygen reduction reaction (ORR), are still highly expected to achieve better performance by modulating the composition and spatial structure of active site. Herein, we constructed the non-planar nest-like [Fe S ] cluster sites in N-doped carbon plane. Adjacent double Fe atoms effectively weaken the O-O bond by forming a peroxide bridge-like adsorption configuration, and the introduction of S atoms breaks the planar coordination of Fe resulting in greater structural deformation tension, lower spin state, and downward shifted Fe d-band center, which together facilitate the release of OH* intermediate.

Constructing Mechanical Shuttles in a Three-dimensional (3D) Porous Architecture for Selective Transport of Lithium Ions.

Lithium (Li) extraction from brines is a major barrier to the sustainable development of batteries and alloys; however, current separation technology suffers from a trade-off between ion selectivity and permeability. Herein, a crown ether mechanically interlocked 3D porous organic framework (Crown-POF) was prepared as the porous filler of thin-film nanocomposite membranes. Crown-POF with penta-coordinated (four O atoms and one N atom) adsorption sites enables a special recognition for Li ion.

Mechanical Bond Approach to Introducing Self-Adaptive Active Sites in Covalent Organic Frameworks for Zinc-Catalyzed Organophosphorus Degradation.

Mechanically interlocked molecules (MIMs) with discrete molecular components linked through a mechanical bond in space can be harnessed for the operation of molecular switches and machines, which shows huge potential to imitate the dynamic response of natural enzymes. In this work, rotaxane compounds were adopted as building monomers for the synthesis of a crown-ether ring mechanically intercalated covalence organic framework (COF). This incorporation of MIMs into open architecture implemented large amplitude motions, whose wheel slid along the axle in response to external stimulation.

Hierarchically Ordered Macro-Microporous Polyoxometalate-Based Metal-Organic Framework Single Crystals.

Facile construction of ordered macroporous polyoxometalate-based metal-organic frameworks (POM@MOFs) to break the intrinsic microporous restriction is significant but remains challenging. On one hand, the POMs introduced improve the structural stability and modify the pores of MOFs, ., introducing functional catalytic and adsorptive units.

Constructing Uranyl-Specific Nanofluidic Channels for Unipolar Ionic Transport to Realize Ultrafast Uranium Extraction.

High-speed capturing of uranyl (UO) ions from seawater elicits unprecedented interest for the sustainable development of the nuclear energy industry. However, the ultralow concentration (∼3.3 μg L) of uranium element leads to the slow ion diffusion inside the adsorbent particle, especially after the transfer paths are occupied by the coexisted interfering ions.

Inorganic nanocrystal-dynamic porous polymer assemblies with effective energy transfer for sensitive diagnosis of urine copper.

Despite their remarkable mechanical, optical, and electrical properties, inorganic particles and dynamic polymer assemblies encounter difficulties in their compatibility with regards to structural order and complexity. Here, covalent organic frameworks (COFs) constructed through reversible coupling reactions were exploited as dynamic porous polymers to prepare inorganic nanocrystal-polymer assemblies. Under an growth process, carbon quantum dots (CDs) were gradually prepared in the COF cavity, with a narrow size distribution (2 ± 0.

Molecularly Imprinted Porous Aromatic Frameworks Serving as Porous Artificial Enzymes.

Artificially designed enzymes are in demand as ideal catalysts for industrial production but their dense structure conceals most of their functional fragments, thus detracting from performance. Here, molecularly imprinted porous aromatic frameworks (MIPAFs) which are exploited to incorporate full host-guest interactions of porous materials within the artificial enzymes are presented. By decorating a porous skeleton with molecularly imprinted complexes, it is demonstrated that MIPAFs are porous artificial enzymes possessing excellent kinetics for guest molecules.

Molecularly Imprinted Porous Aromatic Frameworks and Their Composite Components for Selective Extraction of Uranium Ions.

Selective extraction of uranium from water has attracted worldwide attention because the largest source of uranium is seawater with various interference ions (Na , K , Mg , Ca , etc.). However, traditional adsorbents encapsulate most of their functional sites in their dense structure, leading to problems with low selectivity and adsorption capacities.