Synthesis Of Metal-organic Frameworks Research Articles

Synthesis and characterization of magnetic aluminum metal-organic frameworks encapsulated with chitosan and carboxymethyl cellulose for effective elimination of atrazine from aqueous solutions: Adsorption evaluation, DFT calculations and Box-Behnken design optimization

The discharge of herbicides is a primary contributor to water contamination, presenting significant environmental and public health hazards. Encapsulating herbicides in a chemical compound called MAl-MOF/CS-CMC hydrogel bead (MACC) made from magnetic aluminum metal-organic frameworks (MAl-MOF) and crosslinked with chitosan (CS) and carboxymethyl cellulose (CMC) shows promise for potential use. The research successfully developed and examined MACC microspheres, utilizing various analytical techniques including PXRD, FESEM, TEM, FT-IR, and XPS. The efficiency of MACC in eliminating atrazine (ATZ) from wastewater was also simulated. Additionally, density functional theory (DFT) was employed to assess the electrical characteristics, reactivity, and arrangement of ATZ at a structural level. The results of the DFT analysis demonstrate a significant relationship between the locations of nucleophilic and electrophilic attacks and the molecular orbitals of the HOMO and LUMO. Using MACC as an adsorbent provides considerable advantages due to its expansive surface area of 860.92 m2/g and a pore size of 1.48 nm, meeting the mesoporous classification criteria outlined by IUPAC standards. In addition, it possesses a pore volume of 1.22 cm3/g. Nevertheless, following the adsorption procedure, the pore volume reduced to 0.78 cm3/g, and the surface area decreased to 650.42 m2/g. Several factors contributing to the capacity to attract and retain substances were analyzed. These factors encompass temperature, duration of contact, quantity of the attracting substance, initial atrazine (ATZ) concentration, and solution pH. The primary method of adsorption that was determined is chemisorption, as evidenced by the calculated adsorption energy of 29.3 kJ per mole. The thermodynamic analysis indicates that the adsorption of ATZ by the micropores of MACC occurs spontaneously and is characterized as endothermic, as evidenced by the positive ΔHo value and negative ΔGo value. It has been proposed that a range of adsorption mechanisms, including chemisorption, π-π interactions, pore filling, hydrogen bonding, and electrostatic interactions, may be responsible for removing the herbicide from the MACC material.

Recovery of Bis(2-hydroxyethyl) terephthalate and terephthalic acid from waste PET bottles for synthesis of cerium-based metal-organic frameworks: A study towards supercapacitor applications

Controlled chemical recycling of plastic waste is a most important concern to reduce plastic waste as well as effective recovery of the various byproducts without toxic emission. In this study, we focused on effective recovery of Bis-2-hydroxyethylene terephthalate (r-BHET) from polyethylene terephthalate (PET) waste via solvent free melt depolymerization process. Recovered BHET was converted into terephthalic acid (r-TPA) by hydrolysis. Both r-BHET and r-TPA were used to construct a metal organic framework (MOF) with cerium metal for potential energy applications. Extensive characterization, including Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Field Emission Scanning Electron Microscopy (FE-SEM), and Energy-Dispersive X-ray Spectroscopy (EDX) were confirmed the structural integrity and purity of the r-BHET and r-TPA and provides insights into the well-defined structure and elemental composition of the MOFs. The specific capacitances of BHET and TPA-Ce-MOF were found to be 91.5 and 220.1 F/g respectively. Comprehensive characterization ensures the quality of the recovered products and synthesized MOFs, promoting environmentally conscious strategies in materials synthesis and energy storage applications.

Microfluidic Synthesis of Metal-Organic and Covalent Organic Frameworks: Techniques and Benefits

Microfluidic Synthesis of Metal-Organic and Covalent Organic Frameworks: Techniques and Benefits

MOFSynth: A Computational Tool toward Synthetic Likelihood Predictions of MOFs.

In the past decade, high-throughput computational studies of materials have increased significantly mainly due to advances in computer capabilities and have attracted a great deal of interest. In the field of metal-organic frameworks (MOFs), over a million hypothetical MOFs have been designed in silico, yet only a small fraction of these have been synthesized. For validating the computational-hypothetical results and accelerating the progress in the field, there is a pressing need for distinguishing MOFs that are more likely to be synthesized for real-life applications. This study presents a comprehensive investigation into the synthesizability likelihood of MOFs, utilizing a novel computational approach based on the disparities in energy and geometry between the linker conformation within the MOF structure and its isolated, free-gas state since both of these have been proven to be critical factors influencing MOF synthesis. Our user-friendly tool streamlines synthesizability evaluation, requiring minimal expertise in computational chemistry. By deconstructing over 40,000 MOFs from databases, including QMOF, CoRE MOF, and ToBaCCo, we analyze key parameters defining the linker strain within the MOF unit cell. Our results indicate that QMOF and CoRE MOF contain more promising candidates for synthesis, while ToBaCCo exhibits a relatively poor synthesizability likelihood due to unoptimized materials. Through extensive analysis, we identify optimal linker candidates for highly synthesizable MOFs. Consistent trends in energy distribution across databases that are confirmed by high Pearson and Spearman coefficients suggest the potential for omitting optimization calculations, significantly reducing computational costs. This study underscores the importance of linker deformation and energy disparities and enhances our understanding of synthetic accessibility in MOF research, offering valuable insights for future advancements in the field.

The Synthesis of MOFs of ZnImBImZnO through Hydrothermal and Solvothermal Methods

Metal-organic frameworks (MOFs) are a promising class of materials that have a wide range of applications, from gas storage to catalysis. The synthesis of MOFs from the ZnImBImZnO framework has been carried out using hydrothermal and solvothermal methods. By using different metal-ligand molar ratios and solvents, we have discovered that MOFs can be formed both in DMF and water solvents. The products obtained were studied using various techniques, including SEM, PSA, and FTIR, to confirm their formation Our research has shown that MOFs synthesized with different concentrations and solvents show different size distributions. This suggests that the choice of solvent and concentration can be used to control the size and morphology of the MOFs. Furthermore, we have found that the formation of the MOFs framework also directs the morphology of the Zn(II)-imidazole complex and ZnO NFs. Our results provide important insights into the synthesis and properties of MOFs. Moreover, the contact angle measurement data for the ZnImBImZnO framework indicates that it is unequivocally hydrophilic. By understanding the factors that influence the properties of MOFs, we can design new materials with specific properties tailored to different applications. This exciting research area has the potential to revolutionize many fields, from energy storage to drug delivery. Our results provide important insights into the properties of MOFs and pave the way for developing new materials with tailored properties.

A general flame aerosol route to kinetically stabilized metal-organic frameworks

Metal-organic frameworks (MOFs) are highly attractive porous materials with applications spanning the fields of chemistry, physics, biology, and engineering. Their exceptional porosity and structural flexibility have led to widespread use in catalysis, separation, biomedicine, and electrochemistry. Currently, most MOFs are synthesized under equilibrium liquid-phase reaction conditions. Here we show a general and versatile non-equilibrium flame aerosol synthesis of MOFs, in which rapid kinetics of MOF formation yields two distinct classes of MOFs, nano-crystalline MOFs and amorphous MOFs. A key advantage of this far-from-equilibrium synthesis is integration of different metal cations within a single MOF phase, even when this is thermodynamically unfavorable. This can, for example, produce single-atom catalysts and bimetallic MOFs of arbitrary metal pairs. Moreover, we demonstrate that dopant metals (e.g., Pt, Pd) can be exsolved from the MOF framework by reduction, forming nanoclusters anchored on the MOF. A prototypical example of such a material exhibited outstanding performance as a CO oxidation catalyst. This general synthesis route opens new opportunities in MOF design and applications across diverse fields and is inherently scalable for continuous production at industrial scales.

Concurrent conversion of waste cooking oil using Al metal-organic framework and subcritical methanol through esterification/transesterification process

Recently, some scientists have focused on discovering techniques for manufacturing biodiesel on a significant, efficient, and ecologically sustainable scale. Choosing a catalyst is a notable challenge due to the instability and cost feasibility issues connected with newly designed homogeneous and heterogeneous catalysts. This paper describes the synthesis and utilization of aluminum-based metal-organic frameworks (MOFs) as catalysts for the generation of biodiesel from waste cooking oil (WCO). The processes involved in this study are esterification and transesterification, which are carried out using subcritical methanol. The catalyst analysis reveals that the MOFs possess a filamentous structure, with a crystallite size ranging from 300 to 500 nm. Furthermore, these MOFs exhibit thermal stability up to 470 °C. The catalyst underwent examination for biodiesel production from waste cooking oil (WCO), and the resulting biodiesel samples met the standards set by the American Society for Testing and Materials (ASTM). The experiment was devised and fine-tuned to incorporate the three independent variables using a multilevel factorial design, response surface methodology, and a three-way analysis of variance (ANOVA). The FAME conversion peaked at 91.96 %, as determined through statistical analysis of the optimization findings. The corresponding values for the variables were X1: 423.15 K, X2: 1800s, and X3: 28 mol/mol. Based on ANOVA statistics, the experimental and mathematical verification demonstrates a fair correlation between the actual and calculated catalyst performance. The temperature and molar ratio of methanol: WCO significantly affected the FAME conversion.

Achievements and Challenges in Surfactants-Assisted Synthesis of MOFs-Derived Transition Metal-Nitrogen-Carbon as a Highly Efficient Electrocatalyst for ORR, OER, and HER.

Metal-organic frameworks (MOFs) are excellent precursors for preparing transition metal and nitrogen co-doped carbon catalysts, which have been widely utilized in the field of electrocatalysis since their initial development. However, the original MOFs derived catalysts have been greatly limited in their development and application due to their disadvantages such as metal atom aggregation, structural collapse, and narrow pore channels. Recently, surfactants-assisted MOFs derived catalysts have attracted much attention from researchers due to their advantages such as hierarchical porous structure, increased specific surface area, and many exposed active sites. This review mainly focuses on the synthesis methods of surfactants-assisted MOFs derived catalysts and comprehensively introduces the action of surfactants in MOFs derived materials and the structure-activity relationship between the catalysts and the oxygen reduction reaction, oxygen evolution reaction, and hydrogen evolution reaction performance. Apparently, the aims of this review not only introduce the status of surfactants-assisted MOFs derived catalysts in the field of electrocatalysis but also contribute to the rational design and synthesis of MOFs derived catalysts for fuel cells, metal-air cells, and electrolysis of water toward hydrogen production.

Sustainable synthesis of MOF for COVID-19 detection using a 23 factorial design

The emergence of the COVID-19 pandemic has underscored the urgent requirement for rapid and accurate diagnostic methods to detect the virus and control its spread. Metal Organic Frameworks (MOFs) have gained significant interest in biosensing applications because of their exceptional properties. This study investigates the microwave synthesis of zeolitic imidazolate framework-8 (ZIF-8) and explores its potential as a fluorescent biosensor for detecting COVID-19 RNA sequences. The microwave method enables a rapid, eco-friendly, and efficient synthesis of ZIF-8. Characterization tests including PXRD, FE-SEM, TGA, and FT-IR confirmed the high crystallinity and thermal stability of ZIF-8. To optimize the biosensor’s performance, a 23 factorial design is pursued. The factorial design allows determining the individual and simultaneous effects of the control parameters such as ZIF-8 concentration, buffer pH, and solution temperature on the quenching efficiency. The results demonstrate that the parameters combination of 25 °C, pH 8.0, and 0.7 mg/mL ZIF-8 concentration results in the highest quenching percentage of 72.41 %. The study of the quenching mechanism confirms that the P-DNA can form electrostatic and π-π stacking interactions with ZIF-8, to produce a P-DNA@ZIF-8 complex. It is also found that photoinduced electron transfer is more dominant than fluorescence resonance energy transfer in the quenching mechanism. The biosensor showed a high sensitivity towards the target COVID-19 RNA with a very low detection limit of 12.02 pM, a fast detection time of 40 minutes, and high selectivity to the target RNA. This study shows the potential of ZIF-8 as a feasible and environmentally friendly material for swiftly and accurately detecting COVID-19 RNA sequences.

Selective Separation of Thiophene Derivatives Using Metal-Organic Frameworks-Based Membranes.

The removal of sulfur compounds, particularly thiophene derivatives, from oil is crucial due to concerns about environmental issues. Therefore, the deep desulfurization of transportation fuels is currently an urgent problem, and numerous attempts have been made in this direction. Membrane-based desulfurization can be a good alternative to the traditional hydrodesulfurization method, which has several limitations. In this work, the use of membranes containing a metal-organic framework, MOF-5, doped with transition metals (Ag, Cu, Ni), in the adsorptive desulfurization process was studied. The efficiency of membranes was evaluated based on selective removal of thiophene and dibenzothiophene from model oil. Characterization techniques, including scanning electron microscopic (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), confirmed the successful synthesis and incorporation of metal-organic frameworks (MOFs) into mixed matrix membranes (MMMs). Desulfurization experiments showed that MOF-5/Ag exhibited the highest thiophene adsorption efficiency (86.8%), outperforming MOF-5/Cu and MOF-5/Ni. The enhanced performance is attributed to the strong interaction between silver and sulfur. These findings demonstrate the potential of MOF-based MMMs for efficient and selective desulfurization, offering a viable alternative to traditional hydrodesulfurization (HDS) methods.

Conversion of Carbon Dioxide into Molecular-based Porous Frameworks.

ConspectusThe conversion of carbon dioxide (CO2) to value-added functional materials is a major challenge in realizing a carbon-neutral society. Although CO2 is an attractive renewable carbon resource with high natural abundance, its chemical inertness has made the conversion of CO2 into materials with the desired structures and functionality difficult. Molecular-based porous materials, such as metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs), are designable porous solids constructed from molecular-based building units. While MOF/COFs attract wide attention as functional porous materials, the synthetic methods to convert CO2 into MOF/COFs have been unexplored due to the lack of synthetic guidelines for converting CO2 into molecular-based building units.In this Account, we describe state-of-the-art studies on the conversion of CO2 into MOF/COFs. First, we outline the key design principles of CO2-derived molecular building units for the construction of porous structures. The appropriate design of reactivity and the positioning of bridging sites in CO2-derived molecular building units is essential for constructing CO2-derived MOF/COFs with desired structures and properties. The synthesis of CO2-derived MOF/COFs involves both the transformation of CO2 into building units and the formation of extended structures of the MOF/COFs. We categorized the synthetic methods into three types as follows: a one-step synthesis (Type-I); a one-pot synthesis without workup (Type-II); and a multistep synthesis which needs workup (Type-III).We demonstrate that borohydride can convert CO2 into formate and formylhydroborate that serve as a bridging linker for MOFs in the Type-I and Type-II synthesis, representing the first examples of CO2-derived MOFs. The electronegativity of coexisting metal ions determines the selective conversion of CO2 into formate and formylhydroborate. Formylhydroborate-based MOFs exhibit flexible pore sizes controlled by the pressure of CO2 during synthesis. In pursuit of highly porous structures, we present the Type-I synthesis of MOFs from CO2 via the in situ transformation of CO2 into carbamate linkers by amines. The direct conversion of diluted CO2 (400 ppm) in air into carbamate-based MOFs is also feasible. Coordination interactions stabilize the intrinsically labile carbamate in the MOF lattice. A recent study demonstrates that the Type-III synthesis using alkynylsilane precursors enables the synthesis of highly porous and stable carboxylate-based MOFs from CO2, which exhibit catalytic activity in CO2 conversion. We also extended the synthesis of MOFs from CO2 to COFs. The Type-III synthesis using a formamide monomer affords stable CO2-derived COFs showing proton conduction properties. The precise design of CO2-derived building units enables expansion of the structures and functionalities of CO2-derived MOF/COFs. Finally, we propose future challenges in this field: (i) expanding structural diversity through synthesis using external fields and (ii) exploring unique functionalities of CO2-derived MOF/COFs, such as carriers for CO2 capture and precursors for CO2 transformation. We anticipate that this Account will lay the foundation for exploring new chemistry of the conversion of CO2 into porous materials.

Metal-Organic Frameworks through the Lens of Artificial Intelligence: A Comprehensive Review.

Metal-organic frameworks (MOFs) are a class of hybrid porous materials that have gained prominence as a noteworthy material with varied applications. Currently, MOFs are in extensive use, particularly in the realms of energy and catalysis. The synthesis of these materials poses considerable challenges, and their computational analysis is notably intricate due to their complex structure and versatile applications in the field of material science. Density functional theory (DFT) has helped researchers in understanding reactions and mechanisms, but it is costly and time-consuming and requires bigger systems to perform these calculations. Machine learning (ML) techniques were adopted in order to overcome these problems by implementing ML in material data sets for synthesis, structure, and property predictions of MOFs. These predictions are fast, efficient, and accurate and do not require heavy computing. In this review, we discuss ML models used in MOF and their incorporation with artificial intelligence (AI) in structure and property predictions. The advantage of AI in this field would accelerate research, particularly in synthesizing novel MOFs with multiple properties and applications oriented with minimum information.

In Situ Synthesis of Copper-Based Metal-Organic Frameworks with Ligand Defects for Electrochemical Reduction of CO2 into C2 Products.

Electrochemical reduction of CO2 into high-value-added products is a potential approach to solving environmental problems but is limited by poor product selectivity and low efficiency. Metal-organic framework (MOF) materials have been considered one of the most promising catalysts, but their application is limited by complicated preparation processes, especially during the synthesis of organic ligands. In this work, a new three-dimensional Cu-MOF (JXUST-301) with high porosity was constructed based on the naphthalene diimide (NDI) ligand. Furthermore, JXUST-301 with ligand defects (JXUST-301D) originating from the missing NDI unit was synthesized via an in situ reaction. The presence of ligand defects endows JXUST-301D with a better CO2RR performance with a FEC2 of 56.7% and a jC2 of -162.4 mA cm-2. Mechanistic studies revealed that the hierarchical pore structure and amino sites are created from the absence of the NDI unit, which promotes the exposure of catalytically active sites and CO2 enrichment. Furthermore, the electronic structure of the Cu sites is modulated to upshift the d-band center, facilitating chemical adsorption and activation of key reaction intermediates. This work provides new insight into the in situ preparation of efficient Cu-MOF catalysts by introducing defects for the CO2RR.

Ammonia Storage in Metal-Organic Framework Materials: Recent Developments in Design and Characterization.

Since the advent of the Haber-Bosch process in 1910, the global demand for ammonia (NH3) has surged, driven by its applications in agriculture, pharmaceuticals, and energy. Current methods of NH3 storage, including high-pressure storage and transportation, present significant challenges due to their corrosive and toxic nature. Consequently, research has turned towards metal-organic framework (MOF) materials as potential candidates for NH3 storage due to their potential high adsorption capacities and structural tunability. MOFs are coordination networks composed of metal nodes and organic linkers, offering unprecedented porosity and surface area, and allowing incorporation of various functional groups and metal sites that can enhance NH3 adsorption. However, the stability of MOFs in the presence of NH3 is a significant concern since many degrade upon exposure to NH3, primarily due to ligand displacement and framework collapse. To address this, recent studies have focused on the synthesis and postsynthetic modification of MOFs to enhance both NH3 uptake and stability. In this Account, we summarize recent developments in the design and characterization of MOFs for NH3 storage. The choice of metal centers in MOFs is crucial for stability and performance. High-valence metals such as AlIII and TiIV form strong metal-linker bonds, enhancing the stability of the framework to NH3. The MFM-300 series of materials composed of high-valence 3+ and 4+ metal ions and carboxylic linkers demonstrates high stability and high NH3 uptake capacities. Ligand functionalization is another effective strategy for improving the NH3 adsorption. Polar functional groups such as -NH2, -OH, and -COOH enhance the interaction between the framework and NH3, particularly at low partial pressures, while postsynthetic modification allows fine-tuning of these functionalities to optimize the framework for higher adsorption capacities and stability. For example, MFM-303(Al), incorporating free carboxylic acid groups, exhibits a high NH3 packing density comparable to that of solid NH3. Creating defect sites by removing linkers or adding metal ions increases the number of active sites available for NH3 adsorption and shows promise for enhancing uptake. UiO-66, a stable MOF framework, can be modified to include defect sites, significantly enhancing the level of NH3 uptake. The full characterization of MOFs and especially their interactions with NH3 are vital for understanding and improving their performance. Techniques such as neutron powder diffraction (NPD), inelastic neutron scattering (INS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), electron paramagnetic resonance (EPR) spectroscopy, and solid-state nuclear magnetic resonance (ssNMR) spectroscopy can elucidate host-guest interactions and binding dynamics between NH3 and the framework structure and afford crucial information for the future design and rational development of new sorbents. This Account highlights our current strategies for the synthesis and characterization of MOFs for NH3 capture, providing an overview of this rapidly evolving field.

Two-Dimensional Silver-Isocyanide Frameworks.

Metal-organic frameworks (MOFs) have been widely studied due to their versatile applications and easily tunable structures. However, heteroatom-metal coordination dominates the MOFs community, and the rational synthesis of carbon-metal coordination-based MOFs remains a significant challenge. Herein, two-dimensional (2D) MOFs based on silver-carbon linkages are synthesized through the coordination between silver(I) salt and isocyanide-based monomers at ambient condition. The as-synthesized 2D MOFs possess well-defined crystalline structures and a staggered AB stacking mode. Most interestingly, these 2D MOFs, without π-π stacking between layers, exhibit narrow bandgaps down to 1.42 eV. As electrochemical catalysts for converting CO2 to CO, such 2D MOFs demonstrate Faradaic efficiency over 92%. Surprisingly, the CO2 reduction catalyzed by these MOFs indicates favorable adsorption of CO2 and *COOH on the active carbon sites of the isocyanide groups rather than on silver sites. This is attributed to the critical σ donor role of isocyanides and the corresponding ligand-to-metal charge-transfer effect. This work not only paves the way toward a new family of MOFs based on metal-isocyanide coordination but also offers a rare platform for understanding the electrocatalysis processes on strongly polarized carbon species.

A porous three-dimensional Cu-MOF: Preparation and application in supercapacitors, low temperature hydrogen storage and gas separation

Due to its unique porosity, metal–organic frameworks (MOFs) have great application prospects in the fields of gas adsorption and separation. However, the synthesis of multi-functional MOFs is still a great challenge. Herein, a multi-functional Cu-MOF of {[Cu2(TPTA)(H2O)2]·2DMF·NMP·4H2O}n with a porosity of 62.0 % was designed and synthesized. The H2 adsorption amount of Cu-MOF is about 289.2 cm3 g−1 at 77 K and 1 bar. Meanwhile, the selectivity adsorption of Cu-MOF towards CO2 over CH4 (V:V = 0.5:0.5), CO2/N2 (V:V = 0.5:0.5) and CO2/H2 (V:V = 0.5:0.5) is 95.1, 139.2 and 147.5, respectively, which is 1.5 times higher than the previously reported Cu-MOFs. The Cu-MOF@NF//AC asymmetric supercapacitor demonstrates high specific capacitance (53.4 F g−1) and stability (90.3 % after 2000 cycles). Furthermore, this work presents a novel approach to design multifunctional materials with low temperature hydrogen storage, gas separation and energy storage properties.

A 1,3,5-triazine μ3-bridged neutral Cu(I) framework with enhanced stability and CO2 capture selectivity

Compounds with 1,3,5-triazine ring such as melamine derivatives, known for their low cost and high stability, offer potential for affordable, stable metal organic framework (MOF) synthesis. However, reported such frameworks are facing issues like low stability and reduced porosity. To overcome such problems, we explored organic ligands with protonated nitrogen atoms on the 1,3,5-triazine ring, facilitated by introducing hydroxyl groups on carbon atoms of the triazine ring to construct MOFs. By using 5-azacytosine, we have successfully synthesized SXU-121, a neutral ultramicroporous MOF with eta-topology and high density of open Cu(I) sites. SXU-121 features robust structural stability and significant CO2 adsorption capacity with high selectivity over N2 under ambient conditions. We believe SXU-121's development opens new avenues for creating a class of stable and low cost metal-triazine frameworks with potential diverse functionalities.

Topology-driven directed synthesis of metal-organic frameworks

Topology-driven directed synthesis of metal-organic frameworks

Encapsulating Azolates Within Cationic Metal-Organic Frameworks for High-Energy-Density Materials.

Despite the synthesis of numerous cationic metal-organic frameworks (CMOFs), their counter anions have been primarily limited to inorganic Cl-, NO3 -, ClO4 -, BF4 -, and Cr2O7 2-, which have weak coordination abilities. In this study, a series of new CMOFs is synthesized using azolates with strong coordination abilities as counter anions, which are exclusively employed as ligands for coordinating with metals. Owing to the unique nitrogen-rich composition of azolates, the CMOFs demonstrate significant potential as high-energy-density materials. Notably, CMOF(CuTNPO) has an exceptionally high heat of detonation of 7375kJ kg-1, surpassing even that of the state-of-art CL-20 (6536kJ kg-1). To further validate the advantages of employing azolates as counter anions, analogues with azolates serving as ligands are also synthesized. The comparison study indicates that encapsulating azolates within the cationic frameworks confers both high energy and safety properties. X-ray data and quantum calculations indicate that their enhanced performance stems from stronger H─bonds and π-π interactions. This study introduces new roles for azolates in MOFs and expands possibilities for structural diversity and potential applications of framework materials.

Synthesis and investigation of charge storage characteristics in Ni-MOF/PANI composite as an active electrode material for supercapacitor

This study aimed to develop a more stable and efficient energy storage device, synthesis of nickel-based pristine metal organic framework (MOF) and combined it with the emeraldine base phase of polyaniline (PANI) which is confirmed with XRD, SEM and TEM. Both Ni-MOF and PANI exhibit faradaic (battery-like) behaviour. However, when these two materials are combined, the stability of the resulting material is enhanced. The initial materials, MOF and PANI, exhibit specific capacities of 42 C/g and 72 C/g, respectively. However, when these two materials are combined, their composite exhibits an enhanced specific capacity of 122 C/g. The cyclic voltammetry (CV) analysis shows oxidation and reduction peaks, indicating faradaic behaviour. This behaviour is further confirmed by electrochemical impedance spectroscopy (EIS). Upon comparing it with prior results, the specific capacity appears to be slightly lower. However, it is anticipated to exhibit stronger stability, which is contradictory. The composite material (Ni-MOF/PANI) exhibits remarkable capacitive retention of 99.25 % even after undergoing 5000 cycles, as anticipated. In order to validate the aforementioned findings and determine the extent of the current contribution from capacitive and diffusive control, Dunn's model was employed. The data demonstrates the prevalence of diffusive-controlled (faradaic) current over capacitive current. The highest proportion of current resulting from diffusion is 96 %, achieved at a scan rate of 5 mV/s. The highest proportion of current resulting from capacitance is 24 %, achieved at a scan rate of 300 mV/s. At lower scan rates, the material exhibits a greater faradaic behaviour, whereas at higher scan rates, there is a progressive increase in non-faradaic processes. The insufficient time for diffusive process at higher scan rates is the cause. The Dunn's model with quadratic correction is also performed and comparative results were shown. Overall, the material exhibits more stability and dominance in the faradaic process, which paves the path for improved performance.