2-Methylimidazole Modified Co-BTC MOF as an Efficient Catalyst for Chemical Fixation of Carbon Dioxide

Highly exposed metal atomic active sites in Al2O3/CoNC: Modify reaction pathways by coupling oxygen species

The catalytic oxidation of formaldehyde (HCHO) at ambient temperature is a highly efficient, cost-effective and environmentally friendly approach for formaldehyde removal. Reactive oxygen (O*) and reactive hydroxyl groups (OH*) are the main active species in the catalytic oxidation reaction of HCHO. Therefore, it is crucial to design catalysts that can simultaneously enhance the surface concentrations of O* and OH*, thereby improving their overall catalytic performance. The present study aimed to design an Al2O3/CoNC catalyst featuring layered carbon nitride coupled with metal oxides possessing domain-limited cobalt (Co) metal active sites, to efficiently remove HCHO (≈100 %, 100 ppm, RH=50 %, GSHV=20,000 mL/(g h)) and ensure stability (more than 90 % formaldehyde removal within 450 h) at ambient temperature. The characterization revealed that the interaction between Al2O3-supported metal and CoNC resulted in enhanced confinement of Co, leading to a higher abundance of edge structures exposing more active sites. Additionally, the presence of highly dispersed Co-NX active sites and increased oxygen vacancies effectively facilitated the adsorption and activation processes of HCHO and O2, as well as the adsorption and desorption dynamics of intermediates during the reaction. These factors collectively contributed to an improved catalytic activity. The results of in situ infrared spectroscopy revealed that the catalyst improved the adsorption and activation of O2 and H2O, leading to the rapid generation of substantial amounts of O* and OH*. This synergistic interaction between Al2O3 and CoNC plays a crucial role in the sustained production of O* and OH*, promoting efficient of intermediate decomposition, and ensuring excellent catalytic activity and stability for HCHO.

Impact of copper and cobalt-based metal-organic framework materials on the performance and stability of hole-transfer layer (HTL)-free perovskite solar cells and carbon-based

This article investigates the impact of metal-organic frameworks (MOFs) on the performance and stability of perovskite solar cells (PSCs), specifically focusing on the type of metal and the morphology of the MOF. Two types of MOFs, copper-benzene-1,3,5-tricarboxylate (Cu-BTC MOF) with spherical morphology and cobalt-benzene-1,3,5-tricarboxylate (Co-BTC MOF) with rod morphology, are synthesized and spin-coated on TiO2 substrates to form FTO/TiO2/MOF/CH3NH3PbI3/C-paste PSCs. The morphology and size of the MOFs are characterized by scanning electron microscopy (SEM), and the crystallinity and residual PbI2 of the perovskite films are analyzed by X-ray diffraction (XRD). The results show that the Co-BTC MOF PSC exhibits the highest power conversion efficiency (PCE) of 10.4% and the best stability, retaining 82% of its initial PCE after 264 h of storage in ambient air. The improved performance and stability are attributed to the enhanced crystallinity and reduced residual PbI2 of the perovskite film after Co-BTC MOF modification. The paper showcases the immense potential of MOF-based interlayers to revolutionize PSC technology, offering a path toward next-generation solar cells with enhanced performance and longevity.

Adsorptive stripping voltammetric sensor based on Cd zeolitic imidazole framework-67 for electrochemical detection of sarin simulant

A selective and reliable modified glassy carbon sensor, based on a 1.0% Cd zeolitic imidazole framework-67 modified glassy carbon sensor (GCS2), has been developed for ultrasensitive detection of dimethyl methyl phosphonate (DMMP) in human biological fluid. The synthesis of porous nanoparticles of Cd zeolitic imidazole framework-67 (Cd ZIF-67) was carried out via the hydrothermal method. The resulting Cd ZIF-67 powder emerges with good crystallinity, a rhombic dodecahedral morphology with particle size in the range 300 ~ 500 nm, and a specific surface area of 1780 m2·g-1. Furthermore, the fabricated sensor exhibited superior performance in the detection of DMMP with two linearity ranges of 0.02-2.0 nM and 2.0-9.0 nM and a limit of detection (LOD) of 0.06 pM. The fabricated sensor exhibited good reliability, long-term stability, and repeatability, which are favourable attributes for electroanalytical detection. In addition, the fabricated sensor displayed superior performance without significant interference during the assay of DMMP in a biological fluid (human serum sample) within two linearity ranges of 0.1-1.0 nM and 1.0-6.0 nM and a LOD of 0.03 nM.

MOFs as Versatile Catalysts: Synthesis Strategies and Applications in Value-Added Compound Production

Catalysts played a crucial role in advancing modern human civilization, from ancient times to the industrial revolution. Due to high cost and limited availability of traditional catalysts, there is a need to develop cost-effective, high-activity, and nonprecious metal-based electrocatalysts. Metal-organic frameworks (MOFs) have emerged as an ideal candidate for heterogeneous catalysis due to their physicochemical properties, hybrid inorganic/organic structures, uncoordinated metal sites, and accessible organic sections. MOFs are high nanoporous crystalline materials that can be used as catalysts to facilitate polymerization reactions. Their chemical and structural diversity make them effective for various reactions compared to traditional catalysts. MOFs have been applied in gas storage and separation, ion-exchange, drug delivery, luminescence, sensing, nanofilters, water purification, and catalysis. The review focuses on MOF-enabled heterogeneous catalysis for value-added compound production, including alcohol oxidation, olefin oligomerization, and polymerization reactions. MOFs offer tunable porosity, high spatial density, and single-crystal XRD control over catalyst properties. In this review, MOFs were focused on reactions of CO2 fixation, CO2 reduction, and photoelectrochemical water splitting. Overall, MOFs have great potential as versatile catalysts for diverse applications in the future.

Direct decoration of commercial cotton fabrics by binary nickel-cobalt metal-organic frameworks for flexible glucose sensing in next-generation wearable sensors

Having a prime significance in diagonsing and predicting the dangerous symptoms of chronic diseases in the early stages, special attention has been drawn by wearable glucose-sensing platforms in recent years. Herein, modified commercial cotton fabrics, decorated with binary Ni-Co metal-organic frameworks (NC-MOFs) through a one-pot scalable hydrothermal route, were directly utilized as flexible electrodes for non-enzymatic glucose amperometric sensing. Glucose sensitivities of 105.2 μA mM^-1 cm^-2 and 23 μA mM^-1 cm^-2 were acheived within two distinct linear dynamic ranges of 0.04-3.13 mM and 3.63-8.28 mM, respectively. Receiving benefits from a remarkable glucose sensitivity behavior in co-existence of iso-structures and interferences, rapid response (4.2 s), and remarkable reproducibility and repeatability, NC-MOF-modified cotton fabric electrodes are imensilly promising for developing high-performance wearable glucose sensing platfroms. The sensing performance of fabricated electrodes was further investigated in human blood serum and saliva.

Incorporated Metal–Organic Framework Hybrid Materials for Gas Separation, Catalysis and Wastewater Treatment

The special features of metal–organic frameworks (MOFs), namely, tunable porosity, exceptional structure, high surface area and high adsorption capability enable them to be widely studied in many applications including carbon capture and storage (CCS), biomedical engineering, catalysis and pollutant treatment. Despite these remarkable properties, MOFs are known to be moisture-sensitive, hardly recyclable and expensive in fabrication cost which limits their breakthrough performance in more efficient uses. Recently, extensive studies have been devoted to counter those shortcomings by embedding MOFs with support materials using various series of synthetic designs to yield incorporated MOF hybrid materials to counter their limitations. In view of this interest, this review summarizes the latest developments of incorporated MOFs with various materials, namely, ionic liquids (ILs), membranes and metal species. Pre-synthetic and post-synthetic synthesis methods are also discussed. This review also aims to highlight the factors associated with incorporated MOF performance such as materials selection and mass ratio which could have favorable effects in gas separation, catalysis and wastewater treatment applications. The data indicate that incorporated MOF hybrid materials exhibit exceptional properties including excellent robustness and stability. Correspondingly, in comparison to pristine MOFs, incorporated MOF hybrid materials significantly improve, among others, the gas selectivity, catalyst activity and dye removal efficiency in gas separation, catalysis and wastewater treatment, respectively. In addition, the challenge related to the utilization of this newly incorporated material is mentioned.

Explaining chemical clues of metal organic framework-nanozyme nano-/micro-motors in targeted treatment of cancers: benchmarks and challenges

Nowadays, nano-/micro-motors are considered as powerful tools in different areas ranging from cleaning all types of contaminants, to development of Targeted drug delivery systems and diagnostic activities. Therefore, the development and application of nano-/micro-motors based on metal-organic frameworks with nanozyme activity (abbreviated as: MOF-NZs) in biomedical activities have received much interest recently. Therefore, after investigating the catalytic properties and applications of MOF-NZs in the treatment of cancer, this study intends to point out their key role in the production of biocompatible nano-/micro-motors. Since reducing the toxicity of MOF-NZ nano-/micro-motors can pave the way for medical activities, this article examines the methods of making biocompatible nanomotors to address the benefits and drawbacks of the required propellants. In the following, an analysis of the amplified directional motion of MOF-NZ nano-/micro-motors under physiological conditions is presented, which can improve the motor behaviors in the propulsion function, conductivity, targeting, drug release, and possible elimination. Meanwhile, by explaining the use of MOF-NZ nano-/micro-motors in the treatment of cancer through the possible synergy of nanomotors with different therapies, it was revealed that MOF-NZ nano-/micro-motors can be effective in the treatment of cancer. Ultimately, by analyzing the potential challenges of MOF-NZ nano-/micro-motors in the treatment of cancers, we hope to encourage researchers to develop MOF-NZs-based nanomotors, in addition to opening up new ideas to address ongoing problems.

Designing bimetallic zeolitic imidazolate frameworks (ZIFs) for aqueous catalysis: Co/Zn-ZIF-8 as a cyclic-durable catalyst for hydrogen peroxide oxidative decomposition of organic dyes in water

ZIF-8 is well known hybrid material that is self-assembled from inorganic and organic moieties. It has several potential applications due to its unique structure. One of these potential applications is in advanced oxidation processes (AOP) via a heterogeneous catalysis system. The use of modified ZIF-8/H2O2 for the destruction of the azo dye methyl orange (MO) is presented in this work to explore its efficacy. This work presents the bimetallic Co/Zn-ZIF-8 as an efficient catalyst to promote H2O2 oxidation of the MO dye. Co/Zn-ZIF-8 was synthesized through a hydrothermal process, and the pristine structure was confirmed using XRD, FTIR, and XPS. The Co/Zn-ZIF-8/H2O2 system successfully decolorized MO at the selected pH 6.5. It was found that more than 90% of MO (10 ppm) was degraded within only about 50 minutes. Proposed radical and redox mechanisms are presented for H2O2 decomposition where the redox mechanism is suggested to predominate via a Co(ii)/Co(iii) redox consecutive cyclic process.

Insight into the Photocatalytic Activity of Cobalt-Based Metal–Organic Frameworks and Their Composites

Nowadays, materials with great potential for environmental protection are being sought. Metal–organic frameworks, in particular those with cobalt species as active sites, have drawn considerable interest due to their excellent properties. This review focuses on describing cobalt-based MOFs in the context of light-triggered processes, including dye degradation, water oxidation and splitting, carbon dioxide reduction, in addition to the oxidation of organic compounds. With the use of Co-based MOFs (e.g., ZIF-67, Co-MOF-74) as photocatalysts in these reactions, even over 90% degradation efficiencies of various dyes (e.g., methylene blue) can be achieved. Co-based MOFs also show high TOF/TON values in water splitting processes and CO2-to-CO conversion. Additionally, the majority of alcohols may be converted to aldehydes with efficiencies exceeding 90% and high selectivity. Since Co-based MOFs are effective photocatalysts, they can be applied in the elimination of toxic contaminants that endanger the environment.

Novel porous organic polymers functionalized by metalloporphyrin and phosphonium salts for the efficient synergistic catalysis of CO2 conversion under mild conditions

Metalloporphyrin- and phosphonium-functionalized porous organic polymers (POPs) were fabricated successfully via a post-synthesis modification strategy, which were demonstrated to be efficient heterogeneous catalysts for CO2 conversion.

Polyamine-functionalized imidazolyl poly(ionic liquid)s for the efficient conversion of CO2 into cyclic carbonates

The synergistic effect of polyamine groups and nucleophile (Br−) significantly improved the catalytic performance of N4-PIL-2, which can convert epoxides into cyclic carbonates with excellent yields and selectivity under ambient pressure.

The Significance of Metal Coordination in Imidazole-Functionalized Metal-Organic Frameworks for Carbon Dioxide Utilization

The grafting of imidazole species onto coordinatively unsaturated sites within metal-organic framework MIL-101(Cr) enables enhanced CO₂ capture in close proximity to catalytic sites. The subsequent combination of CO₂ and epoxide binding sites, as shown through theoretical findings, significantly improves the rate of cyclic carbonate formation, producing a highly active CO₂ utilization catalyst. An array of spectroscopic investigations, in combination with theoretical calculations reveal the nature of the active sites and associated catalytic mechanism which validates the careful design of the hybrid MIL-101(Cr).

A rational design of efficient trifunctional electrocatalysts derived from tailored Co2+-functionalized anionic metal-organic frameworks

Strategies for developing efficient energy conversion and storage devices that have been optimized by designing electrode materials is a critical challenge for researchers. Herein, we report the design and synthesis of a series of Co@NC trifunctional electrocatalysts derived from rationally designed cobalt-added anion MOF precursors and preliminarily reveal the relationship between the precursor and corresponding efficient electrocatalysts. Benefiting from the special composition of Co²⁺-doped anion MOFs involving Co²⁺ chelates as the Co²⁺ sources, the resulting CoT@NC electrocatalyst possesses abundant Co/Co-N_x/Co-O_x and multiple active nitrogen sites that are evenly distributed. As expected, the rich variety of active species and hierarchical pore structures endow CoT@NC with excellent performances toward ORR, HER, and OER, including a high half-wave potential value of 0.86 V for ORR and low overpotential values for OER (350 mV) and HER (209 mV) at 10 mA cm^-2 in an alkaline solution. Moreover, we assembled a conventional Zn-air battery with CoT@NC as the air-cathode catalyst, which exhibited excellent rechargeable performance and ultrahigh durability. Moreover, CoT@NC coated on Ni foam was used as both anode and cathode for the overall water-splitting process, which needed a bias voltage of 1.70 V to achieve a current density of 10 mA cm^-2. This study sheds light on the design, fabrication, and regulation of highly active cobalt-based electrocatalysts with abundant active sites and tunable pore structures for electrocatalysis and other applications.