Pd Nanocubes@ZIF-8: Integration of Plasmon-Driven Photothermal Conversion with a Metal-Organic Framework for Efficient and Selective Catalysis

Catalytically active designer crown-jewel Pd-based nanostructures encapsulated in metal-organic frameworks

A series of crown-jewel Pd-based bimetallic nanostructures with tunable composition are fabricated inside the pores of an MOF via a hydride-induced-reduction strategy, exhibiting high activity and stability in the hydrogenation of nitrobenzene.

A Rapid and Facile Detection for Specific Small-Sized Amino Acids Based on Target-Triggered Destruction of Metal Organic Frameworks

Most of the reported metal organic frameworks (MOFs)-based DNA sensors were developed by utilizing the different adsorption capacities of MOFs to different structural DNAs (for example, single-stranded DNAs (ssDNAs) and double-stranded DNAs (dsDNAs)) or ssDNAs with different lengths. Herein, we introduced another strategy for the design of MOFs-based biosensing platforms. We found that specific small-sized amino acids (for example, glycine and serine) could lead to the destruction of the MOFs formed by [Cu(mal)(bpy)]·2H₂O], thus recovering the fluorescence of a fluorophore-labeled ssDNA that had been quenched by MOFs. The corresponding working mechanism was discussed. On the basis of this finding, a mix-and-detect fluorescence method was designed for the turn-on detection of specific small-sized amino acids. The feasibility of its use in real serum samples was also demonstrated. Besides biosensing applications, the discovery of amino acids-triggered destruction of MOFs can also enrich the building blocks of molecular logic gate. As an example, a biomolecular logic gate that performs OR logic operation was constructed using glycine and a DNA strand as inputs.

Ag-NPs embedded in two novel Zn3/Zn5-cluster-based metal–organic frameworks for catalytic reduction of 2/3/4-nitrophenol

Two novel microporous Zn-MOFs consist of different SBUs have been used to embed Ag NPs, resulting in two composite catalysts, which show outstanding catalytic activities toward the reduction of nitrophenol.

Controllable design of tunable nanostructures inside metal–organic frameworks

This review focuses on recent progress in the design of tunable nanoentities encapsulated by metal–organic frameworks (MOFs), with special emphasis on the preparation and synergistic properties of such composites.

Multifunctional metal–organic framework catalysts: synergistic catalysis and tandem reactions

Various active sites incorporated into metal–organic frameworks (MOFs) are suitable for synergistic catalysis and tandem reactions.

Metal–organic frameworks meet metal nanoparticles: synergistic effect for enhanced catalysis

This review highlights recent advances in the hybridization of metal–organic frameworks and metal nanoparticles for their synergistically enhanced catalysis.

Balula S, Cunha-Silva L. Improved catalytic performance of porous metal–organic frameworks for the ring opening of styrene oxide

An emerging strategy to improve the performance of porous metal–organic framework (MOF) materials as heterogeneous catalysts is reported.

Incorporation of CuO NPs into modified UiO-66-NH2 metal–organic frameworks (MOFs) with melamine for catalytic C–O coupling in the Ullmann condensation

The UiO-66-NH₂ is initially modified with melamine via a post-synthetic approach. CuO NPs are then anchored via the available functional groups on the surface of the modified MOF.

Efficient incorporation of diverse components into metal organic frameworks via metal phenolic networks

A general and rapid strategy was explored for metal organic frameworks coating on various core components mediated by metal phenolic networks.

Alternative synthetic approaches for metal–organic frameworks: transformation from solid matters

This review summarizes alternative approaches for MOF synthesis by using solvent-insoluble “solid matters” as cation reservoirs and/or templates.

A core–shell metal–organic-framework (MOF)-based smart nanocomposite for efficient NIR/H2O2-responsive photodynamic therapy against hypoxic tumor cells

In this work, core–shell MOF-based smart nanocomposite UCNPs/MB@ZIF-8@catalase has been constructed for bio-imaging and efficient NIR/H₂O₂-responsive photodynamic therapy against hypoxic tumor cells.

Low-cost CuNi@MIL-101 as an excellent catalyst toward cascade reaction: integration of ammonia borane dehydrogenation with nitroarene hydrogenation

Nitroarene hydrogenation is greatly boosted on coupling with ammonia borane dehydrogenation over low-cost CuNi@MIL-101 with bimetallic CuNi nanoparticles with size of ca. 3 nm.

Controlled Encapsulation of Flower-like Rh-Ni Alloys with MOFs via Tunable Template Dealloying for Enhanced Selective Hydrogenation of Alkyne

For new composite materials with functional nanoparticles (NPs) embedded in metal organic frameworks (MOFs), rational design and precise control over their architectures are imperative for achieving enhanced performance and novel functions. Especially in catalysis, the activity and selectivity of such composite materials are strongly determined by the encapsulation state and thickness of the MOF shell, which greatly influences the diffusion and adsorption of substance molecules onto the NP surface. In this study, MOF-74(Ni)-encapsulated Rh-Ni hierarchical heterostructures (Rh-Ni@MOF-74(Ni)) were successfully constructed using magnetic Rh-Ni-alloyed nanoflowers (NFs) as a self-sacrificial template. Strikingly, the encapsulation state and thickness of the formed MOF shell were well-tuned via template dealloying by changing the Ni content in the Rh-Ni NFs template. More interestingly, such unique Rh-Ni composites encapsulated with MOFs as catalysts could be magnetically recyclable and exhibited enhanced catalytic performance for the selective hydrogenation of alkynes to cis products, owing to the confinement effect of the MOF shell, as compared to their pristine counterparts.

Protein-Metal Organic Framework Hybrid Composites with Intrinsic Peroxidase-like Activity as a Colorimetric Biosensing Platform

Artificial enzyme mimetics have received considerable attention because natural enzymes have some significant drawbacks, including enzyme autolysis, low catalytic activity, poor recovery, and low stability to environmental changes. Herein, we demonstrated a facile approach for one-pot synthesis of hemeprotein-metal organic framework hybrid composites (H-MOFs) by using bovine hemoglobin (BHb) and zeolitic imidazolate framework-8 (ZIF-8) as a model reaction system. Surprisingly, the new hybrid composites exhibit 423% increase in peroxidase-like catalytic activity compared to free BHb. Taking advantages of the unique pore structure of H-MOFs with high catalytic property, a H-MOFs-based colorimetric biosensing platform was newly constructed and applied for the fast and sensitive detection of hydrogen peroxide (H₂O₂) and phenol. The corresponding detection limits as low as 1.0 μM for each analyte with wide linear ranges (0-800 μM for H₂O₂ and 0-200 μM for phenol) were obtained by naked-eye visualization. Significantly, a sensitive and selective method for visual assay of trace H₂O₂ in cells and phenol in sewage was achieved with this platform. The stability of H-MOFs was also examined, and excellent reproducibility and recyclability without losing in their activity were observed. In addition, the general applicability of H-MOFs was also investigated by using other hemeproteins (horseradish peroxidase, and myoglobin), and the corresponding catalytic activities were 291% and 273% enhancement, respectively. This present work not only expands the application of MOFs but also provides an alternative technique for biological and environmental sample assay.

Emerging Multifunctional Metal-Organic Framework Materials

Metal-organic frameworks (MOFs), also known as coordination polymers, represent an interesting type of solid crystalline materials that can be straightforwardly self-assembled through the coordination of metal ions/clusters with organic linkers. Owing to the modular nature and mild conditions of MOF synthesis, the porosities of MOF materials can be systematically tuned by judicious selection of molecular building blocks, and a variety of functional sites/groups can be introduced into metal ions/clusters, organic linkers, or pore spaces through pre-designing or post-synthetic approaches. These unique advantages enable MOFs to be used as a highly versatile and tunable platform for exploring multifunctional MOF materials. Here, the bright potential of MOF materials as emerging multifunctional materials is highlighted in some of the most important applications for gas storage and separation, optical, electric and magnetic materials, chemical sensing, catalysis, and biomedicine.

Photothermal-enhanced catalysis in core-shell plasmonic hierarchical Cu7S4 microsphere@zeolitic imidazole framework-8

A strategy to improve reaction activity via the photothermal effect of plasmonic semiconductor nanomaterials is demonstrated in a core–shell structured catalyst.

Conventional semiconductor photocatalysis based on band-edge absorption remains inefficient due to the limited harvesting of solar irradiation and the complicated surface/interface chemistry. Herein, novel photothermal-enhanced catalysis was achieved in a core–shell hierarchical Cu₇S₄ nano-heater@ZIF-8 heterostructures via near-infrared localized surface plasmon resonance. Our results demonstrated that both the high surface temperature of the photothermal Cu₇S₄ core and the close-adjacency of catalytic ZIF-8 shell contributed to the extremely enhanced catalytic activity. Under laser irradiation (1450 nm, 500 mW), the cyclocondensation reaction rate increased 4.5–5.4 fold compared to that of the process at room temperature, in which the 1.6–1.8 fold enhancement was due to the localized heating effect. The simulated sunlight experiments showed a photothermal activation efficiency (PTAE) of 0.07%, further indicating the validity of photothermal catalysis based on the plasmonic semiconductor nanomaterials. More generally, this approach provides a platform to improve reaction activity with efficient utilization of solar energy, which can be readily extended to other green-chemistry processes.

A Novel CuxO Nanoparticles@ZIF-8 Composite Derived from Core-Shell Metal-Organic Frameworks for Highly Selective Electrochemical Sensing of Hydrogen Peroxide

A novel core-shell heterostructure of CuxO nanoparticles@zeolitic imidazolate framework (CuxO NPs@ZIF-8) was successfully prepared through facile pyrolysis of a nanocrystalline copper-based metal-organic framework [nHKUST-1, i.e., Cu3(BTC)2 (BTC = 1,3,5-benzene-tricarboxylate)]@ZIF-8, based on the different thermal stability of the two metal-organic frameworks (MOFs). The small CuxO NPs derived from nHKUST-1 were uniformly dispersed inside the host material and provided active sites, while ZIF-8 kept the original structure as the molecular sieving shell. Owing to the proper pore shape and pore size of ZIF-8, H2O2 could diffuse through the shell, but bigger molecules could not pass. Thus, the composite material exhibited high selectivity when it was used to construct a H2O2 sensor. In addition, the sensor showed an extended linear detection range (from 1.5 to 21442 μM), low detection limit (0.15 μM), and high sensitivity, due to the good electrocatalysis of CuxO NPs and the synergistic effect of the core-shell structure.

Chemical Sensors Based on Metal-Organic Frameworks

Metal-organic frameworks (MOFs) as chemical sensors have developed rapidly in recent years. There have been many papers concerning this field and interest is still growing. The reason is that the specific merits of MOFs can be utilized to enhance sensitivity and selectivity by various energy/charge transfers occurring among different ligands, ligand, and metal centers, such as from ligands to metal centers or metal centers to ligands, as well as from MOF skeletons to guest species. This review intends to provide an update on recent progress in various applications of different MOF-based sensors on the basis of their luminescent and electrochemical responses towards small molecules, gas molecules, ions (cations and anions), pH, humidity, temperature, and biomolecules. MOF-based sensors function by utilizing different mechanisms, including luminescent responses of "turn-on" and "turn-off", as well as electrochemical responses.

Encapsulation of tungstophosphoric acid into harmless MIL-101(Fe) for effectively removing cationic dye from aqueous solution

H₃PW₁₂O₄₀ was incorporated into cages of harmless MIL-101(Fe). The composite material exhibited excellent adsorption performance for the cationic dyes MB and RhB, can be utilized in the selective capture and separation of organic dyes in water and is reusable and stable.

Fabrication of TiO2@MIL-53 core–shell composite for exceptionally enhanced adsorption and degradation of nonionic organics

We report new strategy based on non-aqueous sol–gel reaction for in situ fabrication of TiO₂@MIL-53 core–shell composites, and show excellent performance of the composites for exceptionally enhanced adsorption and degradation of nonionic organics.

MOF catalysis of FeII-to-FeIII reaction for an ultrafast and one-step generation of the Fe2O3@MOF composite and uranium(vi) reduction by iron(ii) under ambient conditions

Surface is for the first time attested to be one of outstanding merits of metal–organic frameworks (MOFs).

Pressure controlled drug release in a Zr-cluster-based MOF

A Zr-cluster-based MOF ZJU-800 was synthesized with high drug loading capacity for controllable drug delivery from 2 days to 8 days.

Facile preparation of a novel SnO2@UiO-66/rGO hybrid with enhanced photocatalytic activity under visible light irradiation

An effective ternary composite of SnO₂@UiO-66/rGO was designed and synthesized.

Nanostructured Co(ii)-based MOFs as promising anodes for advanced lithium storage

A novel kind of Co-containing metal–organic frameworks (Co-BTC MOFs) are firstly developed as anodes for LIBs with excellent electrochemical performance.

Micro-Cu4I4-MOF: reversible iodine adsorption and catalytic properties for tandem reaction of Friedel–Crafts alkylation of indoles with acetals

I₂@Cu₄I₄-MOF can be a highly heterogeneous catalyst to promote the tandem reaction of Friedel–Crafts alkylation of indoles with acetals under solvent-free conditions at room temperature.