Preparation of MOF(Fe) and its catalytic activity for oxygen reduction reaction in an alkaline electrolyte

Z-scheme heterojunction BiOBr/MIL-100(Fe) visible photocatalytic-permonosulfate degradation of AO7

Metal-organic frameworks (MOFs) have garnered significant interest in the field of photocatalysis. In this study, Z-scheme heterojunction BM-x composites consisting of bismuth bromide oxide (BiOBr) and iron-based metal-organic backbone (MIL-100(Fe)) were successfully synthesized using ethylene glycol as a solvent. The composites were characterized using various techniques. BM-x exhibit abundant functional groups, large specific surface areas, and narrow band gap energy, thus provide numerous active sites for catalytic reactions and respond well to visible light. Notably, BM-7 displays remarkable catalytic activity in a visible light-activated permonosulfate (PMS) system and achieves a degradation rate of 99.02% over 100 mg/L gold orange II (AO7) within 60 min. The effects of BM-7 and PMS addition, initial AO7 concentration, initial pH, inorganic anions, and humic acid on the degradation system were investigated. The proposed mechanism of the Z-scheme heterojunction in the BM-7 photocatalyst demonstrates effective photoelectron transfer from the BiOBr conduction band to the MIL-100(Fe) valence band, resulting in excellent catalytic activity. Radical burst experiments identified 1O2, h+, and ·O2- as the main active substances. BM-7 has high stability and reusability, with a degradation rate reduction of only 14.48% after three recycles. These findings provide valuable insights into using persulfate combined with visible light.

Strong electronic interaction enhanced electrocatalysis of copper phthalocyanine decorated Co-MOF-74 toward highly efficient oxygen evolution reaction

Metal-organic frameworks (MOFs) have been identified as promising electrocatalysts for the oxygen evolution reaction (OER). However, most of the reported MOFs have low electrical conductivity and poor stability, and therefore addressing these problems is crucial for achieving higher electrocatalytic performance. Meanwhile, direct observations of the electrocatalytic behavior, which is of great significance to the understanding of the electrocatalytic mechanism, remain highly challenging. Here, we report on a significant electrocatalytic performance enhancement of Co-MOF-74 for the OER after decoration by copper phthalocyanine (CuPc) molecules. Co-MOF-74@CuPc, synthesized by solvothermal reactions, displays a low overpotential of 293 mV and a robust long-term stability (70 h) at 10 mA cm-2. The enhancement has been attributed to strong electronic interaction between the π-conjugated CuPc molecule and Co-MOF-74, which promotes the electron transfer, increases the electrocatalytic active surface area and regulates the electronic structure during the OER process.

MOF derivatization of multifunctional nanozyme: Peroxidase-like catalytic activity combined with magnetic solid phase extraction for colorimetric detection of Hg2

Nanozyme-based colorimetric sensing has drawn immense attention due to the rapid development of nanozyme in recent years. However, the selectivity of nanozyme-based colorimetric sensing greatly limits its subsequent practical application. It is well known that sample pretreatment can not only improve selectivity by eliminating the sample matrix interference, but also improve sensitivity by enriching trace targets. Based on the easy facile surface modification properties of nanozyme, we rationally designed nanozyme combined with sample pretreatment for colorimetric biosensing, through separation and enrichment, thereby improving the selectivity and sensitivity of the nanozyme colorimetric biosensing. As a proof of concept, the detection of Hg2+ by nanozyme-based colorimetric sensing was used as an example. Magnetic peroxidase-like nanozyme Fe3S4 was designed and synthesized. The selectivity is improved by the specific adsorption of S-Hg bond and the interference elimination after magnetic separation. In addition, the sensitivity is improved by magnetic solid-phase extraction enrichment. Our established colorimetric sensing based on Fe3S4 nanozyme integrated sample pretreatment with an enrichment factor of 100 and the limit of detection (LOD) is 26 nM. In addition, this strategy was successfully applied to detect Hg2+ in environmental water samples. Overall, the strategy showed good selectivity and sensitivity, providing a new practical method for the application of nanozyme-based biosensing in sample pretreatment.

MOF-Enhanced Aluminosilicate Ceramic Membranes Using Non-Firing Processes for Pesticide Filtration and Phytochrome Removal

Aluminosilicates, abundant and crucial in both natural environments and industry, often involve uncontrollable chemical components when derived from minerals, making further chemical purification and reaction more complicated. This study utilizes pure alumina and fumed silica powders as more controllable sources, enhancing aluminosilicate reactivity through room temperature (non-firing) processing and providing a robust framework that resists mechanical stress and high temperature. By embedding iron-based metal-organic frameworks (Fe-MOF/non-firing aluminosilicate membranes) within the above matrix, these ceramic membranes not only preserve their mechanical robustness but also gain significant chemical functionality, enhancing their capacity to removing phytochromes from the vegetables. Sodium hydroxide and sodium silicate were selected as activators to successfully prepare high-strength, non-firing aluminosilicate membranes. These membranes demonstrated a flexural strength of 8.7 MPa under wet-culture conditions with a molar ratio of Al2O3:SiO2:NaOH:Na2SiO3 at 1:1:0.49:0.16. The chlorophyll adsorption of spinach conducted on these membranes showed a removal rate exceeding 90% at room temperature and pH = 9, highlighting its potential for the selective adsorption of chlorophyll. This study underscores the potential of MOF-enhanced aluminosilicate ceramic membranes in environmental applications, particularly for agricultural pollution control.

Recent Advances and Synergistic Effects of Non-Precious Carbon-Based Nanomaterials as ORR Electrocatalysts: A Review

The use of platinum-free (Pt) cathode electrocatalysts for oxygen reduction reactions (ORRs) has been significantly studied over the past decade, improving slow reaction mechanisms. For many significant energy conversion and storage technologies, including fuel cells and metal-air batteries, the ORR is a crucial process. These have motivated the development of highly active and long-lasting platinum-free electrocatalysts, which cost less than proton exchange membrane fuel cells (PEMFCs). Researchers have identified a novel, non-precious carbon-based electrocatalyst material as the most effective substitute for platinum (Pt) electrocatalysts. Rich sources, outstanding electrical conductivity, adaptable molecular structures, and environmental compatibility are just a few of its benefits. Additionally, the increased surface area and the simplicity of regulating its structure can significantly improve the electrocatalyst's reactive sites and mass transport. Other benefits include the use of heteroatoms and single or multiple metal atoms, which are capable of acting as extremely effective ORR electrocatalysts. The rapid innovations in non-precious carbon-based nanomaterials in the ORR electrocatalyst field are the main topics of this review. As a result, this review provides an overview of the basic ORR reaction and the mechanism of the active sites in non-precious carbon-based electrocatalysts. Further analysis of the development, performance, and evaluation of these systems is provided in more detail. Furthermore, the significance of doping is highlighted and discussed, which shows how researchers can enhance the properties of electrocatalysts. Finally, this review discusses the existing challenges and expectations for the development of highly efficient and inexpensive electrocatalysts that are linked to crucial technologies in this expanding field.

The MIL100(Fe)/BaTi0.85Zr0.15O3 nanocomposite with the photocatalytic capability for study of tetracycline photodegradation kinetics

The visible light-active nanocomposite with the photocatalytic capability was facile one-pot solvothermal method successfully synthesized. X-ray diffraction (XRD), Thermogravimetry and Derivative Thermogravimetry (TG-DTG), Scanning Electron Microscopy with Energy Dispersive X-ray Analysis (SEM-EDX), Diffuse Reflectance Spectroscopy (UV-Vis DRS), and Fourier Transform Infra-Red (FT-IR) analysis were employed to characterize the synthetized BaTi_0.85Zr_0.15O3, MIL-100(Fe), and the MIL-100(Fe)/BaTi_0.85Zr_0.15O₃ samples. As a result of the Scherrer equations, the size of grains for MIL-100(Fe), BaTi_0.85Zr_0.15O₃, and MIL-100(Fe)/BaTi_0.85Zr_0.15O₃ was estimated to be 40.81, 12.00, and 22.70 nm, respectively. MIL-100(Fe), BaTi_0.85Zr_0.15O₃, and MIL-100(Fe)/BaTi_0.85Zr_0.15O₃ samples showed bandgap values of 1.77, 3.02, and 2.56 determined from their absorption edge wavelengths. In the photodegraded solutions, chemical oxygen demand (COD) data and tetracycline (TC) absorbencies were used to obtain the rate constants of 0.032 min^-1 and 0.030 min^-1, respectively. This corresponds to t_1/2-values of 27.7 min and 21.7 min, respectively, for the degradation and mineralization of TC molecules during photodegradation process.

Synthesis and physicochemical evaluations of a novel MIL-101(Fe)-PMA-Biochar triple composite photocatalyst activated through visible-light and utilized toward degradation of organic pollutants: optimal operations and kinetics investigations

A triple photocatalytic composite of biochar, metal-organic framework, and phosphomolybdic acid was prepared through hydrothermal treatment of iron (III) chloride hexahydrate, terephthalic acid, lavandulifolia-derived biochar, and phosphomolybdic acid. It was characterized and utilized for photodegradation of Rhodamine-B (RhB) dye under visible-light irradiation. Investigations of reaction variables confirmed that, the highest yield of 96.2% was achieved at ambient temperature using 0.07 g of catalyst at pH of 7, and a dye concentration of 10 ppm. Under these optimum conditions, Methyl Orange (MO) dye was also degraded to yield 93% removal. In addition, the kinetic and thermodynamic parameters for RhB were determined. It was revealed that the photodegradation of RhB followed a pseudo-first-order kinetics with no mass transfer limitations. A corresponding chemical mechanism for this process was also suggested. Adsorption isotherms were investigated for rate of adsorption as well as adsorption capacity of the catalyst under dark conditions. Notably, the catalyst could have been reused for five cycles with a loss of around 20% activity.

Fe/Co-MOF Nanocatalysts: Greener Chemistry Approach for the Removal of Toxic Metals and Catalytic Applications

This study describes the preparation of new bimetallic (Fe/Co)-organic framework (Bi-MOF) nanocatalysts with different percentages of iron/cobalt for their use and reuse in adsorption, antibacterial, antioxidant, and catalytic applications following the principles of green chemistry. The prepared catalysts were characterized using several techniques, including X-ray powder diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy. These techniques proved the formation of MOFs, and the average crystallite sizes were 25.3-53.1, 27.6-67.2, 3.0-18.9, 3.0-12.9, and 3.0-23.6 nm for the Fe-MOF, Co-MOF, 10%Fe:90%Co-MOF, 50%Fe:50%Co-MOF, and 90%Fe:10%Co-MOF samples, respectively. The nanoscale (Fe/Co) Bi-MOF catalysts as efficient heterogeneous solid catalysts showed high catalytic activity with excellent yields and short reaction times in the catalytic reactions of quinoxaline and dibenzoxanthene compounds, in addition to their antioxidant and antibacterial activities. Furthermore, the nanoscale (Fe/Co) Bi-MOF catalysts efficiently removed toxic metal pollutants (Pb²⁺, Hg²⁺, Cd²⁺, and Cu²⁺) from aqueous solutions with high adsorption capacity.

Pt nanoclusters embedded Fe-based metal-organic framework as a dual-functional electrocatalyst for hydrogen evolution and alcohols oxidation

Design and construction of high-efficiency and durable dual-functional electrocatalyst for clean energy electrocatalytic reaction is urgently desirable for mitigating the energy shortage and environmental deterioration issues. Herein, we prepared Pt nanoclusters with exposed (111) face plane embedded Fe-based metal-organic frameworks (Fe-MOF, MIL-100(Fe)) catalyst for electrocatalytic hydrogen evolution reaction (HER) and ethylene glycol oxidation reaction (EGOR). It is noted that the available oxygen sites on the surface of MIL-100(Fe) would form Pt-O interaction with Pt nanoclusters to acquire strong interfacial interaction, which endows Pt/MIL-100(Fe) electrocatalyst effective electron transfer, increasing catalytic active sites, accelerating proton-electron coupling, and improving conductivity. Benefitting from the desirable metal-supports interaction and derive merits for catalysis, the high electrocatalytic activity and durability for HER and EGOR were achieved as expected. Impressively, superior HER performance with higher current density, lower overpotential (46/29 mV in acidic/alkaline electrolyte) and smaller Tafel slope (19.7/37.8 mV dec^-1 in acidic/alkaline electrolyte) were acquired compared to commercial Pt/C. Moreover, Pt/MIL-100(Fe) electrode exhibits a rather high mass activity of 11826 mA mg^-1_Pt and long-term stability for EGOR. The present investigation demonstrates the promise of active metal/MOF combination for the interfacial strategy and rational design of dual-functional electrocatalyst, which has potential applications for future electrocatalysis field.

Bimetallic Metal-Organic Frameworks MIL-53(xAl-yFe) as Efficient Catalysts for H2S Selective Oxidation

Catalytic oxidation of H₂S is a crucial green pathway that can fully convert H₂S into value-added elemental S for commercial use. However, achieving high catalytic stability and S selectivity by traditional-metal-based catalysts still remain a major challenge. Herein, a facile one-step solvothermal strategy is designed for the fabrication of bimetallic MIL-53(xAl-yFe) catalysts. The as-synthesized MIL-53(1Al-5Fe) possesses ample coordinatively unsaturated metal sites, which served as efficient catalytic sites for the selective oxidation of H₂S. As a result, the representative MIL-53(1Al-5Fe) achieves a S yield of nearly 100% at 100-160 °C with almost no obvious decrease of catalytic stability in the run of 30 h. Under the defined reaction conditions, the bimetallic metal-organic frameworks are obviously superior to MIL-53(Al) (49.3%) and MIL-53(Fe) (70.5%) in S yield. This study suggests that the introduction of elemental Al into MIL-53(xAl-yFe) could effectively modulate the electronic properties and spatial configuration of the catalysts, further conducing the adsorption and activation of H₂S and thus accelerating the dissociation of H₂S into a key intermediate S* and improving their catalytic performance.

A novel composite of ionic liquid-containing polymer and metal-organic framework as an efficient catalyst for ultrasonic-assisted Knoevenagel condensation

1-Butyl-3-vinylimidazolium chloride was synthesized and polymerized with acrylamide to furnish an ionic liquid-containing polymer, which was then used for the formation of a composite with iron-based metal-organic framework. The resultant composite was characterized with XRD, TGA, FE-SEM, FTIR, EDS and elemental mapping analyses and its catalytic activity was appraised for ultrasonic-assisted Knoevenagel condensation. The results confirmed that the prepared composite could promote the reaction efficiently to furnish the corresponding products in high yields in very short reaction times. Moreover, the composite exhibited high recyclability up to six runs. It was also established that the activity of the composite was higher compared to pristine metal-organic framework or polymer.

Fe-Based metal–organic frameworks as functional materials for battery applications

This review presents a comprehensive discussion on the development and application of pristine Fe-MOFs in lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, metal–air batteries and lithium–sulfur batteries.

Phthalocyanine-induced iron active species in metal–organic framework-derived porous carbon for efficient alkaline zinc–air batteries

The FePc-encapsulated MOF can be thermally converted into a series of Fe-based active centers embedded into N-doped carbon nanomaterials. It shows good oxygen reduction activity in terms of mass activity, long-term durability and methanol tolerance.

Bisphenol A cleanup over MIL-100(Fe)/CoS composites: Pivotal role of Fe-S bond in regenerating Fe2+ ions for boosted degradation performance

Series of MIL-100(Fe)/CoS composites (MxCy) were facilely fabricated using ball-milling method. The optimum M50C50 exhibited extremely higher Fenton-like catalytic degradation activity toward bisphenol A (BPA) than the pristine MIL-100(Fe) and CoS. The significant improvement of BPA degradation was attributed to the synergetic effect between MIL-100(Fe) and CoS with the synergistic factor being 95.7%, in which the Fe-S bonds formed at the interface of the two components facilitate the Fe³⁺/Fe²⁺ cycle by improving the electron mobility both from Co to Fe and from S to Fe. Furthermore, the influence factors like co-existing inorganic ions and pH values on the catalysis activity of M50C50 were explored. The possible reaction mechanism was proposed and confirmed by both active species capture tests and electron spin resonance (ESR) determinations. It was found that M50C50 demonstrated good reusability and water stability, in which the morphology and structure were not changed obviously after five runs' operation. To our best knowledge, it is the first work concerning the interfacial interaction of Fe-MOF/MSx to promote Fe³⁺/Fe²⁺ cycle in Fe-MOFs for the purpose of organic pollutants degradation in the Fenton-like AOPs system.

Dye-Sensitized Fe-MOF nanosheets as Visible-Light driven photocatalyst for high efficient photocatalytic CO2 reduction

Dye-sensitized system holds great potential for the development of visible-light-responsive photocatalysts not only because it can enhance the light absorption and charge separation efficiency of the systems but also because it can tune the band structure of catalysts. Herein, two-dimensional (2D) Fe-MOF nanosheets (Fe-MNS) with a LUMO potential of 0.11 V (vs. RHE) was prepared. Interestingly, it has been found that when the 2D Fe-MNS catalyst was functionalized with visible-light-responsive [Ru(bpy)]₃²⁺ as a dye-sensitizer, the electrons from the [Ru(bpy)]₃²⁺ can effectively inject into the 2D Fe-MNS, which resulted in a negative shift of the LUMO potential of the 2D Fe-MNS to -0.15 V (vs. RHE). Consequently, the [Ru(bpy)]₃²⁺/Fe-MNS catalytic system exhibits a sound photocatalytic CO₂-to-CO activity of 1120 μmol g^-1h^-1 under visible-light-irradiation. The photocatalytic CO production was further ameliorated by regulating the electronic structure of the 2D Fe-MNS by doping Co ions, achieving a remarkable photocatalytic activity of 1637 μmol g^-1h^-1. This work further supports that the dye-sensitized system is an auspicious strategy worth exploring with different catalysts for the development of visible-light-responsive photocatalytic systems.

Preparation of Mn2O3/MIL-100(Fe) composite and its mechanism for enhancing the photocatalytic removal of rhodamine B in water

In this study, Mn₂O₃/MIL-100(Fe) composite was successfully synthesized by the hydrothermal method and applied for photocatalytic removal of rhodamine B (RhB) in water. The physical and chemical properties of the synthesized materials were characterized by XRD, FTIR, SEM, UV-visible, and BET analyses. Experimental results showed a great enhancement in the photocatalytic ability of the Mn₂O₃/MIL-100(Fe) composite as compared to individual Mn₂O₃ or MIL-100(Fe) under visible light and persulfate activation. The affecting factors such as pH, photocatalyst dose, RhB concentration, and Na₂S₂O₈ concentration were investigated to find out the best conditions for efficient photocatalysis. By conducting a radical quenching test, all radicals of HO˙, SO₄˙^-, ¹O₂, and O₂˙^- were found to be important in photocatalytic decomposition. The mechanism was proposed for the enhancement of photocatalytic RhB removal via band potential calculation, charge separation, surface redox reaction, and key reactive oxidation species. With its durability, reusability, and high efficiency, the Mn₂O₃/MIL-100(Fe) composite emerges as a potential photocatalyst working under visible light for application in wastewater treatment.

Super-Dispersed Fe-N Sites Embedded into Porous Graphitic Carbon for ORR: Size, Composition and Activity Control

Searching for high-efficient, good long-term stability, and low-cost electrocatalysts toward oxygen reduction reaction (ORR) is highly desirable for the development of sustainable energy conversion devices. Iron-nitrogen doped carbon (Fe-N/C) catalysts have been recognized as the most promising candidates for traditional Pt-based catalysts that benefit from their high activity, excellent anti-poisoning ability, and inexpensiveness. Here, a super-dispersed and high-performance Fe-N/C catalyst was derived from chemically Fe-doped zeolitic imidazolate frameworks (ZIFs) by directly bonding Fe ions to imidazolate ligands within 3D frameworks. It produced a series of catalysts, whose sizes could be tuned in the range from 62 to over 473 nm in diameter. After rationally regulating the component and heating treatment, the best ORR activity was measured for the catalyst with a size of 105 nm, which was obtained when the Fe3+/Zn2+ molar ratio was 0.05 and carbonization temperature was 900 °C. It exhibited a high onset potential (Eonset = 0.99 V) and half-wave potential (E1/2 = 0.885 V) compared with a commercial 20% Pt/C catalyst (Eonset = 0.10 V, E1/2 = 0.861 V) as well as much better durability and methanol resistance in an alkaline electrolyte.

Composite of MOF and chitin as an efficient catalyst for photodegradation of organic dyes

A novel composite has been fabricated by using MOF and chitin as a natural and biocompatible compound. To this purpose, MOF was synthesized by using 2-aminoterephthalic acid and iron (III) chloride hexahydrate and then reacted with Cl-functionalized chitin. The resulting composite was characterized and utilized as a catalyst for degradation of methylene blue both in dark condition and under visible light irradiation. The results indicated superior catalytic activity under visible light irradiation. Furthermore, study of the reaction variables, including basicity, dye concentration and catalyst loading showed that the highest catalytic activity was achieved at basic condition. It was also found that both initial dye concentration and catalyst loading can affect the catalytic activity. To disclose the merits of the composite compared to its individual components, kinetic studies of the photo-degradation process in the presence of the composite, chitin and MOF have been performed. The results confirmed superior activity the composite compared to its components. The study of the mechanism of the reaction using scavengers confirmed that the created holes (h⁺) are the most effective species in the process of photocatalytic degradation of MB. Notably, the catalyst was recyclable and could be used for degradation of other dyes.

Bifunctional PGM-free metal organic framework-based electrocatalysts for alkaline electrolyzers: trends in the activity with different metal centers

In order to solely rely on renewable and efficient energy sources, reliable energy storage and production systems are required. Hydrogen is considered an ideal solution as it can be produced electrochemically by water electrolysis and renewably while no pollutants are released when consumed. The most common catalysts in electrolyzers are composed of rare and expensive precious group metals. Replacing these materials with Earth-abundant materials is important to make these devices economically viable. Metal organic frameworks are one possible solution. Herein we demonstrate the synthesis and characterization studies of metal benzene-tri-carboxylic acid-based metal-organic frameworks embedded in activated carbon. The conductive composite material was found to be electrocatalytically active for both the oxygen evolution reaction and the hydrogen evolution reaction. Furthermore, several metal organic frameworks sharing the same ligand but with different first-row transition metals (M = Co, Cu, Fe, Mn) were compared, and the trend of their activity is discussed. Cobalt was found to have the highest activity among the studied metal centers, and therefore has the best potential to serve as a bifunctional catalyst for alkaline electrolyzers.

Bifunctional Bi12O17Cl2/MIL-100(Fe) composites toward photocatalytic Cr(VI) sequestration and activation of persulfate for bisphenol A degradation

Bifunctional Bi₁₂O₁₇Cl₂/MIL-100(Fe) composite (BMx) was firstly constructed via facile ball-milling method. The optimal BM200 was highly efficient for Cr(VI) sequestration and activation of persulfate (PS) for bisphenol A (BPA) decomposition under white light illumination, which was much more remarkable than the pristine MIL-100(Fe) and Bi₁₂O₁₇Cl₂, respectively. Furthermore, the photocatalytic reduction efficiency can be significantly improved via the addition of some green small organic acids (SOAs). As well, the BPA degradation can be achieved over an extensive initial pH range of 3.0-11.0. When the PS concentration increased to more than 2.0 mM, the BPA degradation efficiency decreased due to the SO₄^-• self-scavenging effect. It was also found that the co-existence of inorganic anions like H₂PO₄^-, HCO₃^-, SO₄^2-, Cl^- and NO₃^- could decelerate the BPA degradation. The excellent photocatalytic Cr(VI) reduction and persulfate activation performances originated from both MIL-100(Fe) with excellent PS activation ability and Bi₁₂O₁₇Cl₂ with a favorable band position, which not only enabled the efficient separation of charges but also accelerated the formation of SO₄^-• radicals. The BM200 displayed prominent stability and recyclability. More importantly, the credible degradation pathway was proposed based on UHPLC-MS analysis and DFT calculation. This research revealed that the Fe-based MOFs/bismuth-rich bismuth oxyhalides (Bi_xO_yX_z, X = Cl, Br and I) composites possessed great potential in wastewater remediation.

Fe-based metal-organic frameworks as heterogeneous catalysts for highly efficient degradation of wastewater in plasma/Fenton-like systems

Fe-based metal organic frameworks (Fe-MOFs) were successfully synthesized with the dielectric barrier discharge (DBD) plasma method and FeSO4·7H2O as the Fe precursor. Fe-MOFs were used as Fenton-like catalysts in DBD plasma/Fenton-like technology to treat wastewater, which addressed the issues with iron solubility. Since the valence state of iron will affect the catalytic performance, the Fe precursor FeSO4·7H2O was added to regulate the valence state and adjust the catalytic performance by improving the availability of active sites. The influences of discharge voltage, catalyst addition amount, H2O2 addition amount and pH on the degradation efficiency of methyl orange (MO) were systematically examined. Through free radical capture experiments, the reaction mechanism of the plasma/Fenton-like catalytic degradation process was deduced primarily as the coordinated oxidation process of hydroxyl radicals (·OH), photo-generated holes (h+) and superoxide radicals (·O2 -). The reusability experiments proved that the catalyst was stable and reusable. The possible degradation pathways were proposed based on the identification of intermediate products generated in the degradation process by liquid chromatography-mass spectrometry (LC-MS) analyses.

Mitigation the release of toxic PH3 and the fire hazard of PA6/AHP composite by MOFs

Aluminum hypophosphite (AHP) is a high-efficiency phosphorus-based flame retardant with high P content, which is widely used in Polyamide 6 (PA6). However, AHP releases phosphine gas (PH₃) at high temperatures, which is highly toxic to human's health and environment. Metal-organic frameworks (MOFs) have porous structure exhibiting high performance in gas adsorption. Therefore, mesoporous iron (III) carboxylate [MIL-100 (Fe)] was synthesized in this work and employed to study the adsorption capacity of toxic PH₃ in PA6/AHP composite during processing. AHP was combined with melamine cyanurate (MCA) and MIL-100 (Fe) followed by blending with PA6 to prepare PA6 composites (PA6/MA and PA6/MAF). PA6/MAF with the weight ratio of 5:5 performed well in inhibiting the release of PH₃ during the processing of composite as well as the accelerated thermal experiment devised by our group. Besides, PA6/MAF (5:5) showed relatively low fire hazard reflected by the reduction of the peak of heat release rate of PA6 composite from 962 to 260 kW/m² compared with that of pure PA6 in the cone calorimeter test, and MIL-100 (Fe) along with MCA also presented synergistic effect in suppressing the emission of carbon monoxide. The subtle selection of MOFs herein has the potential to be used as a promising synergist for hazardous gases released from polymer composites to improve the occupational and fire safety in the society.

Iron-Based Metal-Organic Frameworks as Platform for H2S Selective Conversion: Structure-Dependent Desulfurization Activity

Three classical Fe-MOFs, viz., MIL-100(Fe), MIL-101(Fe), and MIL-53(Fe), were synthesized to serve as platforms for the investigation of structure-activity relationship and catalytic mechanism in the selective conversion of H₂S to sulfur. The physicochemical properties of the Fe-MOFs were characterized by various techniques. It was disclosed that the desulfurization performances of Fe-MOFs with well-defined microstructures are obviously different. Among these, MIL-100(Fe) exhibits the highest catalytic performance (ca. 100% H₂S conversion and 100% S selectivity at 100-180 °C) that is superior to that of commercial Fe₂O₃. Furthermore, the results of systematic characterization and DFT calculation reveal that the difference in catalytic performance is mainly because of discrepancy in the amount of Lewis acid sites. A plausible catalytic mechanism has been proposed for H₂S selective conversion over Fe-MOFs. This work provides critical insights that are helpful for rational design of desulfurization catalysts.

Development of Nickel-BTC-MOF-Derived Nanocomposites with rGO Towards Electrocatalytic Oxidation of Methanol and Its Product Analysis

In this study, electrochemical oxidation of methanol to formic acid using the economical and highly active catalytic Nickel Benzene tricarboxylic acid metal organic framework (Ni-BTC-MOF) and reduced graphene oxide (rGO) nanocomposites modified glassy carbon electrode GCE in alkaline media, which was examined via cyclic voltammetry technique. Nickel based MOF and rGO nanocomposites were prepared by solvothermal approach, followed by morphological and structural characterization of prepared samples through X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and energy dispersive X-ray (EDX) analysis. The electrochemical testing of synthesized materials represents the effect of the sequential increase in rGO concentration on electrocatalytic activity. The Ni-BTC/4 wt % rGO composite with a pronounced current density of 200.22 mA/cm2 at 0.69 V versus Hg/HgO electrode at 50 mV/s was found to be a potential candidate for methanol oxidation in Direct Methanol Fuel Cell (DMFC) applications. Product analysis was carried out through Gas Chromatography (GC) and Nuclear Magnetic Resonance (NMR) spectroscopy, which confirmed the formation of formic acid during the oxidation process, with approximately 62% yield.

Comparison of new metal organic framework-based catalysts for oxygen reduction reaction

In this article, we collected the most significant and recent data in brief in the field of metal organic frameworks oxygen reduction reaction catalysts, obtained from some of the most recent research papers in the field. We present lists of materials and their key parameters that are relevant to the cathode catalysts in polymer electrolyte membrane fuel cells. All the materials listed in this paper are composed of metal organic frameworks, zeolitic imidazolate frameworks, or their derivatives. These are divided into two main groups: pristine MOFs and MOF-derived materials. The data in this article is a summary of more extensive review (Gonen and Elbaz, 2018) [1].