Recent Advances of Bimetallic-Metal Organic Frameworks: Preparation, Properties, and Fluorescence-Based Biochemical Sensing Applications

Bimetallic-metal organic frameworks (BiM-MOFs) or bimetallic organic frameworks represent an innovative and promising class of porous materials, distinguished from traditional monometallic MOFs by their incorporation of two metal ions alongside organic linkers. BiM-MOFs, with their unique crystal structure, physicochemical properties, and composition, demonstrate distinct advantages in the realm of biochemical sensing applications, displaying improvements in optical properties, stability, selectivity, and sensitivity. This comprehensive review explores into recent advancements in leveraging BiM-MOFs for fluorescence-based biochemical sensing, providing insights into their design, synthesis, and practical applications in both chemical and biological sensing. Emphasizing fluorescence emission as a transduction mechanism, the review aims to guide researchers in maximizing the potential of BiM-MOFs across a broader spectrum of investigations. Furthermore, it explores prospective research directions and addresses challenges, offering valuable perspectives on the evolving landscape of fluorescence-based probes rooted in BiM-MOFs.

Boosting hydrogen production of a MOF-based multicomponent photocatalyst with clean interface via facile one-pot electrosynthesis

Hydrogen production from photocatalysis via the usage of multicomponent photocatalysts represents a promising pathway for carbon peaking and carbon neutrality, owing to their structural advantages in dealing with the three crucial processes in photocatalysis, namely, light harvesting, charge transfer, and surface redox reactions. We demonstrate the fabrication of a MOF-based multicomponent photocatalyst, denoted as semiconductor/MOF/cocatalyst, by a one-pot electrochemical synthetic route. The as-fabricated multicomponent photocatalyst has a clean interface among the components, leading to close connections that contribute to high-quality heterojunction and facilitate photogenerated charge transfer and separation, thereby the efficient hydrogen evolution. The hydrogen production rate of the resultant ZrO2 /Zr-MOF/Pt is 1327 μmol ⋅ g-1  ⋅ h-1 , which is much higher than that of ZrO2 /Zr-MOF (15 μmol ⋅ g-1  ⋅ h-1 ) and pure Zr-MOF (10.1 μmol ⋅ g-1  ⋅ h-1 ), as well as the photodeposited-Pt products ZrO2 /Zr-MOF/PtPD (287 μmol ⋅ g-1  ⋅ h-1 ) and Zr-MOF/PtPD (192 μmol ⋅ g-1  ⋅ h-1 ) obtained by the step-wise synthetic approach. The work gives a good inspiration for the rational design and construction of MOF-based multicomponent photocatalysts through the one-pot electrosynthesis.

Construction of N-Doped Carbon-Modified Ni/SiO2 Catalyst Promoting Cinnamaldehyde Selective Hydrogenation

At present, the selective hydrogenation of α, β-unsaturated aldehydes remains a challenge due to competition between unsaturated functional groups (C=C and C=O). In this study, N-doped carbon deposited on silica-supported nickel Mott-Schottky type catalysts (Ni/SiO₂@N_xC) was prepared for the selective hydrogenation of cinnamaldehyde (CAL) by using the respective hydrothermal method and high-temperature carbonization method. The prepared optimal Ni/SiO₂@N₇C catalyst achieved 98.9% conversion and 83.1% selectivity for 3-phenylpropionaldehyde (HCAL) in the selective hydrogenation reaction of CAL. By constructing the Mott-Schottky effect, the electron transfer from metallic Ni to N-doped carbon at their contact interface was promoted, and the electron transfer was demonstrated by XPS and UPS. Experimental results indicated that by modulating the electron density of metallic Ni, the catalytic hydrogenation of C=C bonds was preferentially performed to obtain higher HCAL selectivity. Meanwhile, this work also provides an effective way to design electronically adjustable type catalysts for more selective hydrogenation reactions.

Rational Design and Growth of MOF-on-MOF Heterostructures

Multiporous metal-organic frameworks (MOFs) have emerged as a subclass of highly crystalline inorganic-organic materials, which are endowed with high surface areas, tunable pores, and fascinating nanostructures. Heterostructured MOF-on-MOF composites are recently becoming a research hotspot in the field of chemistry and materials science, which focus on the assembly of two or more different homogeneous or heterogeneous MOFs with various structures and morphologies. Compared with one single MOF, the dual MOF-on-MOF composites exhibit unprecedented tunability, hierarchical nanostructure, synergistic effect, and enhanced performance. Due to the difference of inorganic metals and organic ligands, the lattice parameters in a, b, and c directions in the single crystal cells could bring about subtle or large structural difference. It will result in the composite material with distinct growth methods to obtain secondary MOF grown from the initial MOF. In this review, the authors wish to mainly outline the latest synthetic strategies of heterostructured MOF-on-MOFs and their derivatives, including ordered epitaxial growth, random epitaxial growth, etc., which show the tutorial guidelines for the further development of various MOF-on-MOFs.

High performance of ultrasonic-assisted synthesis of two spherical polymers for enantioselective catalysis

Chiral polymers have aroused great attention in among chiral supramolecular materials based on their features. Herein, for the first time, the synthesis of chiral polymeric composites (CMNPs/1,4-Zbtb & 1,3-Zbtb) have been reported with entrapment through three strategies: ultrasonic irradiation, solvothermal, and mechanical stirring. According to the obtained results, it is found that ultrasound-assisted synthesis can be considered as an inexpensive and efficient method than the others, from the point ofviewof energy and time consuming. In this strategy, encapsulation of chiral magnetic nanoparticles (CMNPs) by using tetrazole-based polymers (Zbtbs) happens, in-situly. These chiral sphere-like inorganic-organic polymers can be considered as core and shell composites with catalytic activity due to their acidic (semi unsaturated Zn: open metal sites) and basic (abundant basic nitrogens) centers. In these structures, the unprecedented chirality induction can happen from the core to shell by non-covalent interaction, easily. They could catalyze symmetric oxidation and asymmetric henry condensation to give chiral β-nitroalkanol. Circular dichroism and chiral gas chromatography were used to characterize the produced enantiomers. These chiral polymeric materials can be considered as unique acid-base bifunctional catalysts with efficient properties such as high stability, enantiomeric excess, enantioselectivity to the main product, and protecting from CMNPs leaching.

The role of metal–organic porous frameworks in dual catalysis

Metal–organic frameworks (MOFs) are a valuable group of porous crystalline solids with inorganic and organic parts that can be used in dual catalysis.

The function of metal-organic frameworks in the application of MOF-based composites

In the last two decades, metal-organic frameworks (MOFs), as a class of porous crystalline materials formed by organic linkers coordinated-metal ions, have attracted increasing attention due to their unique structures and wide applications. Compared to single components, various well-designed MOF-based composites combining MOFs with other functional materials, such as nanoparticles, quantum dots, natural enzymes and polymers with remarkably enhanced or novel properties have recently been reported. To efficiently and directionally synthesize high-performance MOF-based composites for specific applications, it is vital to understand the structural-functional relationships and role of MOFs. In this review, preparation methods of MOF-based composites are first summarized and then the relationship between the structure and performance is determined. The functions of MOFs in practical use are classified and discussed through various examples, which may help chemists to understand the structural-functional relationship in MOF-based composites from a new perspective.

In Situ One-Step Synthesis of Platinum Nanoparticles Supported on Metal-Organic Frameworks as an Effective and Stable Catalyst for Selective Hydrogenation of 5-Hydroxymethylfurfural

A facile in situ one-step route for the preparation of platinum nanoparticles supported on metal-organic frameworks (MOFs) without adding stabilizing agents was developed. The obtained 10% Pt@MOF-T3 material possessed a large surface area and high crystallinity. Meanwhile, uniform and well-dispersed platinum nanoparticles were formed inside the cavities of MOFs, which could be attributed to the efficient complexation and stabilization effect derived from the dipyridyl groups. The as-synthesized 10% Pt@MOF-T3 sample showed high activity and selectivity in the hydrogenation of 5-hydroxymethylfurfural (HMF). This excellent catalytic performance could be attributed to the synergistic effects of well-dispersed platinum nanoparticles and electron donation offered by MOFs. Meanwhile, the presence of bipyridine ligands in the MOF framework avoided the irreversible adsorption of the hydrocarbon compounds, leading to the enhanced catalytic efficiency. Besides, it was easily recycled and reused at least five times, showing good recyclability.

Bimetallic metal-organic frameworks and their derivatives

Bimetallic metal-organic frameworks (MOFs) have two different metal ions in the inorganic nodes. According to the metal distribution, the architecture of bimetallic MOFs can be classified into two main categories namely solid solution and core-shell structures. Various strategies have been developed to prepare bimetallic MOFs with controlled compositions and structures. Bimetallic MOFs show a synergistic effect and enhanced properties compared to their monometallic counterparts and have found many applications in the fields of gas adsorption, catalysis, energy storage and conversion, and luminescence sensing. Moreover, bimetallic MOFs can serve as excellent precursors/templates for the synthesis of functional nanomaterials with controlled sizes, compositions, and structures. Bimetallic MOF derivatives show exposed active sites, good stability and conductivity, enabling them to extend their applications to the catalysis of more challenging reactions and electrochemical energy storage and conversion. This review provides an overview of the significant advances in the development of bimetallic MOFs and their derivatives with special emphases on their preparation and applications.

A Smart Route for Encapsulating Pd Nanoparticles into a ZIF-8 Hollow Microsphere and Their Superior Catalytic Properties

The encapsulation of catalytically active noble metal nanoparticles (NM NPs) into metal-organic frameworks (MOFs) represents an effective strategy for enhancing their catalytic performance. Despite a myriad of reports on the nanocomposites consisting of NM NPs and MOFs, it remains challenging to develop a sustainable and convenient method for realizing confined integration of NM NPs within a porous and hollow zinc-based MOF. Herein, a simple and well-designed approach is reported to the fabrication of Pd@ZIF-8 hollow microspheres with a number of Pd nanoparticles immobilized on the inner surface. This method capitalized on the use of polyvinylpyrrolidone (PVP)-stabilized polystyrene (PS) microspheres as templates, to harness the dual functions of PVP for reducing PdCl₂ to generate Pd NPs and coordinating with zinc ions to grow ZIF-8 shells. Consequently, it avoids the complicated protocols involving surface treatment of template microspheres that conventionally adopts hazardous or costly agents. The obtained Pd@ZIF-8 hollow microspheres exhibit outstanding catalytic activity, size selectivity, and stability in the hydrogenation of alkenes. This study presents both the advances in the green synthesis and great potential of Pd@ZIF-8 hollow microspheres for catalytic applications.

Metal organic frameworks for biomass conversion

This review narrates the recent developments on the catalytic applications of pristine metal–organic frameworks (MOFs), functionalized MOFs, guests embedded over MOFs and MOFs derived carbon composites for biomass conversion into platform chemicals.

Monodisperse NiPd alloy nanoparticles decorated on mesoporous graphitic carbon nitride as a catalyst for the highly efficient chemoselective reduction of α,β-unsaturated ketone compounds

The study reported chemoselective reduction with selectivity (>99%) by the catalytic transfer hydrogenation of α,β-unsaturated ketones with a catalyst of NiPd alloy nanoparticles decorated on mesoporous graphitic carbon nitride (NiPd/mpg-C₃N₄).

Metal-Organic Frameworks Encapsulating Active Nanoparticles as Emerging Composites for Catalysis: Recent Progress and Perspectives

Beyond conventional porous materials, metal-organic frameworks (MOFs) have aroused great interest in the construction of nanocatalysts with the characteristics of catalytically active nanoparticles (NPs) confined into the cavities/channels of MOFs or surrounded by MOFs. The advantages of adopting MOFs as the encapsulating matrix are multifold: uniform and long-range ordered cavities can effectively promote the mass transfer and diffusion of substrates and products, while the diverse metal nodes and tunable organic linkers may enable outstanding synergy functions with the encapsulated active NPs. Herein, some key issues related to MOFs for catalysis are discussed. Then, state-of-the art progress in the encapsulation of catalytically active NPs by MOFs as well as their synergy functions for enhanced catalytic performance in the fields of thermo-, photo-, and electrocatalysis are summarized. Notably, encapsulation-structured nanocatalysts exhibit distinct advantages over conventional supported catalysts, especially in terms of the catalytic selectivity and stability. Finally, challenges and future developments in MOF-based encapsulation-structured nanocatalysts are proposed. The aim is to deliver better insight into the design of well-defined nanocatalysts with atomically accurate structures and high performance in challenging reactions.

Metal–Organic Framework Hybrid Materials and Their Applications

The inherent porous nature and facile tunability of metal–organic frameworks (MOFs) make them ideal candidates for use in multiple fields. MOF hybrid materials are derived from existing MOFs hybridized with other materials or small molecules using a variety of techniques. This led to superior performance of the new materials by combining the advantages of MOF components and others. In this review, we discuss several hybridization methods for the preparation of various MOF hybrids with representative examples from the literature. These methods include covalent modifications, noncovalent modifications, and using MOFs as templates or precursors. We also review the applications of the MOF hybrids in the fields of catalysis, drug delivery, gas storage and separation, energy storage, sensing, and others.

The development of MOFs-based nanomaterials in heterogeneous organocatalysis

Metal-organic framework (MOF) is a class of inorganic-organic hybrid material assembled periodically with metal ions and organic ligands. MOFs have always been the focuses in a variety of frontier fields owing to the advantageous properties, such as large BET surface areas, tunable porosity and easy-functionalized surface structure. Among the various application areas, catalysis is one of the earliest application fields of MOFs-based materials and is one of the fastest-growing topics. In this review, the main roles of MOFs in heterogeneous organocatalysis have been systematically summarized, including used as support materials (or hosts), independent catalysts, and sacrificial templates. Moreover, the application prospects of MOFs in photocatalysis and electrocatalysis frontiers were also mentioned. Finally, the key issues that should be conquered in future were briefly sketched in the final parts of each item. We hope our perspectives could be beneficial for the readers to better understand these topics and issues, and could also provide a direction for the future exploration of some novel types of MOFs-based nanocatalysts with stable structures and functions for heterogeneous catalysis.

One-pot sustainable synthesis of magnetic MIL-100(Fe) with novel Fe3O4 morphology and its application in heterogeneous degradation

A novel, rapid and simple method is described for the synthesis of magnetic MIL-100(Fe) with novel Fe₃O₄ morphology, which significantly improved the sustainability of conventional fabrication processes in several aspects. The magnetic MOFs were prepared (i) in one pot (instead of multiple steps), (ii) at room temperature (instead of temperatures over 150 °C), (iii) within a few hours with excellent yield (instead of in few days with low productivity) and (iv) in the absence of any corrosive inorganic acid and organic reagent. The materials were tested in the industrially demanded photocatalytic and photo-Fenton degradation of sodium sulfadiazine. The degradation results indicated that the Fe₃O₄ nanorods could accelerate the catalytic efficiency. The catalyst would be of potential application due to its stable catalytic activity in repeated reaction cycles and no need for regeneration. Therefore, the MIL-100(Fe) and magnetic MIL-100(Fe) proposed in this study are ideal catalysts for the heterogeneous degradation of sodium sulfadiazine.

Encapsulation of metal nanostructures into metal–organic frameworks

Recent developments in controlling the location, composition, shape, and structure of metal nanostructures in MOFs for a variety of applications.

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.

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.

Fe3O4@HKUST-1 and Pd/Fe3O4@HKUST-1 as magnetically recyclable catalysts prepared via conversion from a Cu-based ceramic

A Fe₃O₄/Cu- ceramic system converted into a magnetic HKUST-1 composite was used as a recyclable catalyst for one-pot cascade and hydrogenation reactions.

The Road to MOF-Related Functional Materials and Beyond: Desire, Design, Decoration, and Development

Metal-organic frameworks (MOFs), which are known as a class of porous coordination polymers, have proven to be of great significance to manifold applications, owing to their fascinating topology, ultrahigh porosity, enormous internal surface area, and the combination of being as rigid as inorganic materials and as flexible as organic materials . In this review, we give a concise history of the development of MOFs as functional materials prior to our entry into this area in 2006, then a summary of our road to participate in and extend the outline of the research in MOFs chemistry, as well as the challenge in further designing applicable functional materials. We describe not only the road of evolution from the past, present, and future of this chemistry, but also the road to finalize a functional material from the desire to the design, synthesis, and postmodification of a MOF. Throughout the review, we particularly emphasize the improvements in the application of MOFs as heterogeneous catalysts, such as employing MOFs as one component for the construction of composites, and their extended scope in tough catalytic reactions. Examples of applications in gas storage and separation, small molecular sensing, and our perspectives for future applications triggered by MOFs, are also introduced.

Particle size effects in the selective hydrogenation of cinnamaldehyde over supported palladium catalysts

Palladium particles of different sizes obtained directly and indirectly by various methods were studied to clarify the particle size effect in the selective hydrogenation of cinnamaldehyde (CAL).

Low-temperature catalytic oxidation of CO over highly active mesoporous Pd/CeO2–ZrO2–Al2O3catalyst

Addition of zirconium and aluminum into Pd/CeO₂led to an increase of surface atomic ratios of Ce³⁺/Ce⁴⁺andO_adsorbed/O_lattice, pore volume, ratios and size of mesopores, catalytic activity, as well as decrease of particle size,E_aandT₁₀₀(60 °C).

Metal–organic framework MIL-101 supported bimetallic Pd–Cu nanocrystals as efficient catalysts for chromium reduction and conversion of carbon dioxide at room temperature

A series of bimetallic Pd–Cu nanocrystals supported on the zeolite-type metal–organic framework MIL-101 and their application in the reduction of Cr(vi) to Cr(iii) using formic acid and the conversion of terminal alkynes into propiolic acids with CO₂ are reported.