Features Of Metal-organic Frameworks Research Articles

Active learning of alchemical adsorption simulations; towards a universal adsorption model.

Adsorption is a fundamental process studied in materials science and engineering because it plays a critical role in various applications, including gas storage and separation. Understanding and predicting gas adsorption within porous materials demands comprehensive computational simulations that are often resource intensive, limiting the identification of promising materials. Active learning (AL) methods offer an effective strategy to reduce the computational burden by selectively acquiring critical data for model training. Metal-organic frameworks (MOFs) exhibit immense potential across various adsorption applications due to their porous structure and their modular nature, leading to diverse pore sizes and chemistry that serve as an ideal platform to develop adsorption models. Here, we demonstrate the efficacy of AL in predicting gas adsorption within MOFs using "alchemical" molecules and their interactions as surrogates for real molecules. We first applied AL separately to each MOF, reducing the training dataset size by 57.5% while retaining predictive accuracy. Subsequently, we amalgamated the refined datasets across 1800 MOFs to train a multilayer perceptron (MLP) model, successfully predicting adsorption of real molecules. Furthermore, by integrating MOF features into the AL framework using principal component analysis (PCA), we navigated MOF space effectively, achieving high predictive accuracy with only a subset of MOFs. Our results highlight AL's efficiency in reducing dataset size, enhancing model performance, and offering insights into adsorption phenomenon in large datasets of MOFs. This study underscores AL's crucial role in advancing computational material science and developing more accurate and less data intensive models for gas adsorption in porous materials.

Post-Synthetic Modifications of Ti(IV)-Based Metal-Organic Frameworks for Enhanced Photocatalysis and Conductivity

Metal-Organic Frameworks (MOFs) are coordination networks with organic ligands containing potential voids, ideal for guest-host interactions. These unique characteristics make them interesting materials for several different applications, including catalysis. Unfortunately, most MOFs feature metal oxide nodes that are insulting by nature, which limits their potential in electro- and photochemical catalysts. To combat these issues, post-synthetic modifications (PSM) can be used to tune MOF properties. This research reports on different PSMs incorporated into the Ti(IV)-based MOFs MIL-125(Ti) and MIL-125(Ti)-NH2. PSMs that introduce intentional defect states and dopant metal ions, such as Ce(IV), were explored to determine their influence on the photo-degradation of Rhodamine B in aqueous solution. Post-Synthetic Metal Exchange (PSME) was used to incorporate Ce(IV) at the Ti(IV) sites in MIL-125(Ti) and MIL-125(Ti)-NH2, and intentional defect states were introduced using formic acid during MOF synthesis. In addition, conductive organic polymers were utilized to make novel polymer-MOF hybrid composites that showed enhanced charge transport properties compared to pristine MOF. Ultimately, these results show how PSMs can be used to impart conductivity and enhance photocatalysis in the MOFs MIL-125(Ti) and MIL-125(Ti)-NH2.

Metal-Organic-Framework-Based Nanoarrays for Oxygen Evolution Electrocatalysis.

The development of highly active and stable electrode materials for the oxygen evolution reaction (OER) is essential for the widespread application of electrochemical energy conversion systems. In recent years, various metal-organic frameworks (MOFs) with self-supporting array structures have been extensively studied because of their high porosity, abundant metal sites, and flexible and adjustable structures. This review provides an overview of the recent progress in the design, preparation, and applications of MOF-based nanoarrays for the OER, beginning with the introduction of the architectural advantages of the nanoarrays and the characteristics of MOFs. Subsequently, the design principles of robust and efficient MOF-based nanoarrays as OER electrodes are highlighted. Furthermore, detailed discussions focus on the composition, structure, and performance of pristine MOF nanoarrays (MOFNAs) and MOF-based composite nanoarrays. On the one hand, the effects of the two components of MOFs and several modification methods are discussed in detail for MOFNAs. On the other hand, the review emphasizes the use of MOF-based composite nanoarrays composed of MOFs and other nanomaterials, such as oxides, hydroxides, oxyhydroxides, chalcogenides, MOFs, and metal nanoparticles, to guide the rational design of efficient OER electrodes. Finally, perspectives on current challenges, opportunities, and future directions in this research field are provided.

Shaping Methods of Metal–Organic Frameworks for Natural Gas Storage

The eco-friendly advantages of cleaner fuels such as natural gas have been extensively documented. However, the practical utilization of these fuels is restricted by the limitations of existing gas storage technologies. In this discussion, this paper evaluates the broad spectrum of possibilities that gas fuels present for transforming the energy sector, while also addressing the hindrances posed by current storage technologies that impede this transition. This paper scrutinizes the practical implications of natural gas storage, employing crystalline, porous metal-organic frameworks (MOFs) while referring to the latest benchmark outcomes and ultimate storage objectives in this domain. Specifically, this delve into the industrial constraints posed by the typically powdered form of MOFs and emphasize the recent advancements in MOF shaping. In contrast to their unprocessed powder condition, the features of MOFs as shaped in this study are examined, and a full review of several structuring methods is provided. The industrial usage of MOFs in applications involving gas processing is anticipated to be accelerated by this research.

Application of MOFs in Hydrogen Storage

This research analyzes the current energy problems and environmental problems and proposes to use hydrogen energy as a clean alternative energy source, which has high energy density and less pollution. After comparing the advantages and disadvantages of various hydrogen storage solutions, metal-organic frameworks (MOFs) are selected as the storage and transportation medium because of its large capacity, favourable reversibility, appropriate reaction conditions and relatively low density. The hydrogen storage mechanism of MOFs and the factors affecting its hydrogen storage capacity are introduced and discuss some methods to improve the storage features of MOFs. Three promising, MOFs, MOF-5, MIL-101 and NU-1501, are listed and their storage performance and specific structure are introduced. The current problems in the application and processing of partial hydrogen storage MOFs are proposed, and some feasible solutions and processing methods are introduced. Finally, the application prospects of MOFs are prospected and suitable development directions are proposed, which will be helpful for future research.

Electrochemiluminescence Properties and Sensing Application of Zn(II)-Metal-Organic Frameworks Constructed by Mixed Ligands of Para Dicarboxylic Acids and 1,10-Phenanthroline.

Four metal-organic frameworks (MOFs) were designed and prepared through a mixed-ligand strategy by controlling the combination of various dicarboxylic acid ligands with invariant center metal and o-phenanthroline heterocyclic ligand. The regulatory effects of ligand electronic band and crystal structure on the electrochemiluminescence (ECL) characteristics of MOFs were verified by experimental results and density functional theory (DFT) calculations. The flexible chain structure of MOF-2 promotes electron transfer between MOF electroactive free radicals and the co-reactant, making it show outstanding ECL characteristics among all of the four MOFs with the luminescence quantum efficiency 8.37 times that of tris(bipyridine)-ruthenium(II) ([Ru(bpy)3]2+). Meanwhile, a new ECL mechanism for MOF luminescent crystal materials with reactive oxygen species in solvents as a co-reactant in the aqueous aerobic environment has been proposed. MOF-2 was selected to construct an ECL sensor for the determination of glucose in human urine samples. This study provides a useful idea for the development and design of new luminescent molecular crystal materials.

Assessment of synthesis conditions on the corrosion inhibitive features of ZIF-67 MOF

Metal-organic frameworks (MOFs) have indeed attracted substantial interest owing to their distinctive features and diverse applications, such as corrosion protection. In this work, using two synthesis methods, namely co-precipitation (CZ67) and solvothermal (SZ67), a cobalt-based zeolitic imidazole framework (ZIF-67) was developed as an essential family of MOFs. The results of the characterization confirmed that ZIF-67 particles were synthesized successfully. According to the results of XRD, FE-SEM, TEM, ICP-OES, TGA, and BET analysis, the SZ67 has a higher surface area and higher stability in solution compared to CZ67. In addition, CZ67 and SZ67 were introduced in epoxy coatings to form CZ67/EPC and SZ67/EPC. The SZ67/EPC exhibited greater corrosion inhibition activity than the CZ67/EPC. After 24 h of exposure to the salty media, the|Z|at the low frequency for the scratched SZ67/EPC (119,500 Ω.cm2) reached 1.1 and 5.7 times of that for the CZ67/EPC and Neat epoxy coatings, respectively. Furthermore, SZ67/EPC demonstrated superior barrier anticorrosion properties during immersion for forty days. The corrosion protection and adhesion performance of SZ67/EPC surpassed the rest of the coated samples after salt spray exposure.

Mono-coordinated defect toward metal-organic framework anode with remarkable electrochemical performance

The ultrahigh porosity and ligand tunability features of Metal organic frameworks (MOFs) make them excellent platforms for energy conversion and storage. Nevertheless, the practical applications of these materials are restricted due to their low conductivity and insufficient redox sites. Herein, a mono-coordinated ferrocenecarboxylic acid (Fc) was incorporated into MIL-53(Al) via a straightforward hydrothermal process to regulate the local coordination structure. In comparison to the MIL-53(Al) with a capacity of only 113 mAh/g, the MIL-53(Al)-Fc anode delivered an ultrahigh reversible capacity of 823 mAh/g over 700 cycles at 1 A·g−1. Furthermore, the developed MIL-53(Al)-Fc anode can exhibit a super high rate capacity of 489 mAh/g at 2 A/g. Importantly, it is discovered that the incorporation of Fc-doped MIL-53(Al) leads to a sustained increase in capacity throughout the process of charge/discharge cycling. Through a combination of experimental analysis and theoretical calculations, it has been demonstrated that the presence of unsaturated coordination metal sites into Fc-doped MIL-53(Al) not only improve its conductivity and the kinetics of Li+ storage, but also expose more reaction sites for Li+ facile desorption. This, in turn, facilitate the order–disorder transition during cycles. Meanwhile, the 1D nanorods morphologies can provide superior interaction between the active sites and electrolyte. Thus, this work will pave a new way to engineer advanced MOFs electrode materials for practical utilization of ultrahigh performance LIBs.

Accurately predicting the performance of MOF-based mixed matrix membranes for CO2 removal using a novel optimized extreme learning machine by BAT algorithm

The increasing number of mixed matrix membranes (MMMs) based on metal organic frameworks (MOFs) for carbon capture has created a demand for accurate and swift evaluation of their separation performance. Machine learning (ML) has emerged as a valuable tool for this purpose, providing an efficient approach for screening these materials and accelerating their practical application. In this study, we developed and optimized a novel and reliable hybrid machine learning paradigm based on the extreme learning machines (ELM) method using the BAT algorithm optimization. In order to predict the performance of MMMs, including gas permeability and selectivity parameters, nine machine learning models were developed by incorporating descriptors and fingerprints for polymer featurization, physical and structural features of MOFs as well as operating conditions. The impact of input features on MMMs performance was also explored using RReliefF analysis. The study found that the performance of the hybrid ELM-based algorithms was significantly improved by using the BAT algorithm. Furthermore, the RReliefF analysis revealed that the cage size of the MOF and the type of polymer matrix used are the most significant parameters in forecasting the permeability of MOF-based MMMs, while the loading amount and pressure were identified as critical determinants of selectivity. Overall, these findings contribute to the development of more efficient and accurate methods for evaluating MMMs, which are crucial for carbon capture applications.

Theoretical isotherm equation for adsorption-induced structural transition on flexible metal–organic frameworks

Flexible metal-organic frameworks (MOFs) exhibit an adsorption-induced structural transition known as "gate opening" or "breathing," resulting in an S-shaped adsorption isotherm. This unique feature of flexible MOFs offers significant advantages, such as a large working capacity, high selectivity, and intrinsic thermal management capability, positioning them as crucial candidates for revolutionizing adsorption separation processes. Therefore, the interest in the industrial applications of flexible MOFs is increasing, and the adsorption engineering for flexible MOFs is becoming important. However, despite the establishment of the theoretical background for adsorption-induced structural transitions, no theoretical equation is available to describe S-shaped adsorption isotherms of flexible MOFs. Researchers rely on various empirical equations for process simulations that can lead to unreliable outcomes or may overlook insights into improving material performance owing to parameters without physical meaning. In this study, we derive a theoretical equation based on statistical mechanics that could be a standard for the structural transition type adsorption isotherms, as the Langmuir equation represents type I isotherms. The versatility of the derived equation is shown through four examples of flexible MOFs that exhibit gate opening and breathing. The consistency of the formula with existing theories, including the osmotic free energy analysis and intrinsic thermal management capabilities, is also discussed. The developed theoretical equation may lead to more reliable and insightful outcomes in adsorption separation processes, further advancing the direction of industrial applications of flexible MOFs.

Highly Efficient Propyne/Propylene Separation in a "Flexible-Robust" and Hydrolytically Stable Cu(II)-MOF.

Propyne/propylene separation is important in the petrochemical industry but challenging due to their similar physical properties and close molecular sizes. Metal-organic frameworks (MOFs) are a class of promising adsorbents for light hydrocarbon separations. Among them, the so-called "flexible-robust" MOFs combine the advantages of flexibility and rigidity in structure and could show enhanced gas separation selectivity as well as improved gas uptake at low pressure. Interpenetrated MOFs offer a platform to explore the "flexible-robust" feature of MOFs based on their subnetwork displacement in the process of gas adsorption. Herein, we present two hydrolytically stable MOFs (BUT-308 and BUT-309) with interpenetrated structures and fascinating propyne/propylene separation performance. BUT-308 is composed of interpenetrated 2D Cu(BDC-NH2)BPB layers (H2BDC-NH2 = 2-aminobenzene-1,4-dicarboxylic acid; BPB = 1,4-bis(4-pyridyl)benzene), while BUT-309 consists of twofold interpenetrated 3D pillared-layer Cu2(BDC-NH2)2(BPB-CF3) nets (BPB-CF3 = 2-trifluoromethyl-1,4-bis(4-pyridyl)benzene). Gas adsorption measurements showed that BUT-309 was a "flexible-robust" adsorbent with multistep adsorption isotherms for C3H4 rather than C3H6 at a wide temperature range. The guest-dependent pore-opening behavior endows BUT-309 with high potential in the C3H4/C3H6 separation. The C3H4 adsorption measurements of BUT-309 at 273-323 K showed that the lowering of the temperature induced the pore-opening action at lower pressure. Column breakthrough experiments further confirmed the capability of BUT-309 for the efficient removal of C3H4 from a C3H4/C3H6 binary gas, and the C3H6 processing capacity at 273 K (15.7 cm3 g-1) was higher than that at 298 K (35.2 cm3 g-1). This work shows a rare example of "flexible-robust" MOFs and demonstrated its high potential for C3H4/C3H6 separation.

A Photosensitizing Metal–Organic Framework as a Tandem Reaction Catalyst for Primary Alcohols from Terminal Alkenes and Alkynes

AbstractOwing to the wide and growing demand for primary alcohols, the development of efficient catalysts with high regioselectivity remains a worthwhile pursuit. However, according to Markovnikov's rule, it is a challenge to obtain primary alcohols with high yields and regioselectivity from terminal alkenes or alkynes. Herein, we report the synthesis of a photosensitizing two‐dimensional (2D) metal–organic framework (MOF) from cyclic trinuclear copper(I) units (Cu‐CTUs) and a boron dipyrro‐methene (Bodipy) ligand. The MOF features broadband light absorption, excellent photoinduced charge separation efficiency, and photochemical properties. By integrating the copper‐catalyzed hydroboration and photocatalyzed aerobic oxidation, it can catalyze terminal alkenes and alkynes to produce primary alcohols via a one‐pot tandem reaction with excellent regioselectivity, good overall yields in two‐step reactions (up to 85 %), broad substrate compatibility (32 examples) and good reusability under mild conditions.

A Photosensitizing Metal-Organic Framework as a Tandem Reaction Catalyst for Primary Alcohols from Terminal Alkene and Alkyne.

Due to the wide and growing demand for primary alcohols, the development of efficient catalysts with high regioselectivity remains a worthwhile pursuit. However, according to the Markovnikov's rule, it is challenge to obtain primary alcohols with high yields and regioselectivity from terminal alkenes or alkynes. Herein, we reported the synthesis of a photosensitizing two-dimensional (2D) metal-organic framework (MOF) from cyclic trinuclear copper(I) units (Cu-CTUs) and boron dipyrro-methene (Bodipy) ligand. The MOF features broadband light absorption, excellent photoinduced charge separation efficiency, and photochemical properties. By integrating the copper-catalyzed hydroboration and photocatalyzed aerobic oxidation, it can catalyze terminal alkenes and alkynes to produce primary alcohols via one-pot tandem reaction with excellent regioselectivity, good overall yields in two-step reactions (up to 85%), broad substrate compatibility (32 examples) and good reusability under mild conditions.

Assembling Triphenylene-Based Metal-Organic Framework Nanosheets at the Air/Liquid Interface: Modification by Tuning the Spread Solution Concentration.

Metal-organic frameworks (MOFs)─crystalline coordination polymers─with unique characteristics such as structural designability accompanied by tunable electronic properties and intrinsic uniform nanopores have become the platform for applications in diverse scientific areas ranging from nanotechnology to energy/environmental sciences. To utilize the superior features of MOF in potential applications, the fabrication and integration of thin films are of importance and have been actively sought. Especially, downsized MOFs into nanosheets can act as ultimately thin functional components in nanodevices and potentially display unique chemical/physical properties rarely seen in bulk MOFs. Assembling nanosheets by aligning amphiphilic molecules at the air/liquid interface has been known as the Langmuir technique. By utilizing the air/liquid interface as a reaction field between metal ions and organic ligands, MOFs are readily formed into the nanosheet state. The expected features in MOF nanosheets including electrical conduction largely depend on the nanosheet characteristics such as lateral size, thickness, morphology, crystallinity, and orientation. However, their control has not been achieved as yet. Here, we demonstrate how changing the concentration of a ligand spread solution can modify the assembly of MOF nanosheets, composed of 2,3,6,7,10,11-hexaiminotriphenylene (HITP) and Ni2+ ions (HITP-Ni-NS), at the air/liquid interface. A systematic increase in the concentration of the ligand spread solution leads to the enlargement of both the lateral size and the thickness of the nanosheets while retaining their perfect alignment and preferred orientation. On the other hand, at much higher concentrations, we find that unreacted ligand molecules are included in HITP-Ni-NS, introducing disorder in HITP-Ni-NS. These findings can develop further sophisticated control of MOF nanosheet features, accelerating fundamental and applied studies on MOFs.

A Protophilic MOF Enables Ni-Rich Lithium-Battery Stable Cycling in a High Water/Acid Content.

Trace protic impurities, such as water and hydrofluoric acid (HF), can severely degrade the stable and long cycling of lithium batteries. Therefore, the costly water removal process is inevitably needed throughout production of lithium batteries, leaving the paradox that energy-saving lithium-battery technology consumes non-negligible amounts of energy. Herein, a unique ionic metal-organic framework (MOF) is reported that enables highly destructive H2 O/HF-tolerant lithium batteries. The isolated ionic fluorine sites in the MOF exhibit unusual protophilicity and efficiently capture ppm-levels H2 O/HF from the highly polar electrolyte solvents. The resulting MOF-based LiNi0.6 Mn0.2 Co0.2 O2 │Li battery achieves over 300 cycles in the presence of 800ppm H2 O or 1107ppm acidic impurity. This tenfold longer battery lifespan relative to those for batteries with conventional standard separators demonstrates its excellent electrochemical cycling performance. The results reveal that the rational use of unique nanoporous features of MOFs can provide new possibilities for long-standing challenges in the lithium-battery industry.

Synergistic effect of carbon nanotube and tri-metallic MOF nanoarchitecture for electrochemical high-performance asymmetric supercapacitor applications and their charge storage mechanism

To develop innovative energy-storage devices, metal-organic frameworks (MOFs) with various nano-geometries must be rationally combined. In this research, a trimetallic-based MOF with varying ratios of carbon nanotubes (CNT) was synthesized and optimized for use in electrochemical supercapacitor devices. The composite material has a corrugated-layered structure that allows for fast ion transport and electrolyte storage. The synergistic features of CNT and MOF, along with the stronger redox reactions of multimetallic ionic species, enable effective charge storage. The 1D nanotube form of CNT provides stability and electrical conductivity. MOF-CNT(5 %) showed a higher capacitive efficiency than MOF due to its high specific capacitance and rate capacity (86.1 % retention at 5 A/g). The MOF-CNT(5 %)//ACarbon composite exhibited a capacitance of 166.4 F/g at 1 A/g, 79.2 % retention after 10,000 charging/discharging cycles, a high-power density of 501.5 W/kg, and an energy density of 23.6 Wh/kg, making it a potential nanomaterial for asymmetric supercapacitors. Dunn's and Trasatti's model were used to extract regression parameters and capacitive-diffusive contributions of the supercapacitor.

Synthesis, Crystal Structure, and Photocatalytic Properties of Two Isoreticular Ce(IV)-MOFs with an Infinite Rod-Shaped Inorganic Building Unit.

The use of the V-shaped linker molecules 4,4'-oxydibenzoic acid (H2ODB) and 4,4'-carbonyldibenzoic acid (H2CDB) led to the discovery of two isoreticular Ce(IV)-based metal-organic frameworks (MOFs) of composition [CeO(H2O)(L)], L = ODB2-, CDB2-, denoted CAU-58 (CAU = Christian-Albrechts-University). The recently developed Ce-MOF synthesis approach in acetonitrile as the solvent proved effective in accessing Ce(IV)-MOF structures with infinite rod-shaped inorganic building units (IBUs) and circumventing the formation of the predominantly observed hexanuclear [Ce6O8] cluster. For the structure determination of the isoreticular MOFs, three-dimensional electron diffraction (3D ED) and powder X-ray diffraction (PXRD) data were used in combination with density functional theory (DFT) calculations. [CeO(H2O)(CDB)] shows reversible H2O adsorption by stirring in water and thermal treatment at 190 °C, which leads to a unit cell volume change of 11%. The MOFs feature high thermal stabilities (T > 290 °C), which exceed those of most Ce(IV)-MOFs and can be attributed to the infinite rod-shaped IBU. Surface and bulk oxidation states of the cerium ions were analyzed via X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy (XANES). While Ce(III) ions are observed by the highly surface-sensitive XPS method, the bulk material contains predominantly Ce(IV) ions according to XANES. Application of the MOFs as catalysts for the catalytic degradation of methyl orange in aqueous solutions was also studied. While degradation activity for both MOFs was observed, only CAU-58-ODB revealed enhanced photocatalytic activity under ultraviolet (UV) light. The photocatalytic mechanism likely involves a ligand-to-metal charge transfer (LMCT) from the linkers to the Ce(IV) centers. Analyses by XANES and inductively coupled plasma-optical emission spectroscopy (ICP-OES) demonstrate that leaching of Cerium ions as well as partial reduction of Ce(IV) to Ce(III) takes place during catalysis. At the same time, PXRD data confirm the structural stability of the remaining MOF catalysts.

BioMOF-Based Anti-Cancer Drug Delivery Systems.

A variety of nanomaterials have been developed specifically for biomedical applications, such as drug delivery in cancer treatment. These materials involve both synthetic and natural nanoparticles and nanofibers of varying dimensions. The efficacy of a drug delivery system (DDS) depends on its biocompatibility, intrinsic high surface area, high interconnected porosity, and chemical functionality. Recent advances in metal-organic framework (MOF) nanostructures have led to the achievement of these desirable features. MOFs consist of metal ions and organic linkers that are assembled in different geometries and can be produced in 0, 1, 2, or 3 dimensions. The defining features of MOFs are their outstanding surface area, interconnected porosity, and variable chemical functionality, which enable an endless range of modalities for loading drugs into their hierarchical structures. MOFs, coupled with biocompatibility requisites, are now regarded as highly successful DDSs for the treatment of diverse diseases. This review aims to present the development and applications of DDSs based on chemically-functionalized MOF nanostructures in the context of cancer treatment. A concise overview of the structure, synthesis, and mode of action of MOF-DDS is provided.

Structural Compromise Between Conflicted Spatial-Arrangements of Two Linkers in Metal-Organic Frameworks.

The structural control of metal-organic frameworks (MOFs) is essential for the development of superlative MOFs because the structural features of MOFs and their components play a critical role in determining their properties, and ultimately, their applications. The best components to endow the desired properties for MOFs are available via the appropriate choice from many existing chemicals or synthesizing new ones. However, to date, considerably less information exists regarding fine-tuning the MOF structures. Herein, a strategy for tuning MOF structures by merging two MOF structures into a single MOF, is demonstrated. Depending on the incorporated amounts and relative contributions of the two coexisting organic linkers, benzene-1,4-dicarboxylate (BDC2- ) and naphthalene-1,4-dicarboxylate (NDC2- ), which have conflicting spatial-arrangement preferences within an MOF structure, MOFs are rationally designed to have a Kagomé or rhombic lattice. In particular, MOFs with rhombic lattices are constructed to have specific lattice angles by compromising the optimal structural arrangements between the two mixed linkers. The relative contributions of the two linkers during MOF construction determine the final MOF structures, and the competitive influence between BDC2- and NDC2- is effectively regulated to produce specific MOF structures with controlled lattices.

RETRACTED: Metal-organic framework-based nanostructured catalysts: Applications in biomass conversion

The need for sustainable and ecofriendly materials has grown due to practical considerations over the past few decades. Metal-organic frameworks (MOFs) have drawn significant interest due to their distinctive and intriguing chemical and physical properties as they have been utilized in a variety of chemistries to convert biomass into biofuels and other useful processes. The transformation of glucose into 5-hydroxymethylfurfural (HMF) or levulinic acid, HMF into 2,5-furandicarboxylic acids, vanillin into 2-methoxy-4-methylphenol, and other transformations are discussed in this review article wherein these conversions have been promoted by a variety of MOF-based catalysts, with relevantly enhanced green credentials. Selected examples are discussed for various processes that exploit the reusability aspect, catalysts' reactivity with the inherent MOFs properties and features benefits, together with potential drawbacks of the catalysts also discussed along with future perspectives.