3D-monoclinic M–BTC MOF (M = Mn, Co, Ni) as highly efficient catalysts for chemical fixation of CO2 into cyclic carbonates

A Versatile Metal-Organic-Framework Pillared Interlayer Design for High-Capacity and Long-Life Lithium-Sulfur Batteries

Developing high-performance lithium-sulfur batteries is a promising way to attain higher energy density at a lower cost beyond the state-of-the-art lithium-ion battery technology. However, the major issues impeding their practical applications are the sluggish kinetics and the parasitic shuttling reactions of sulfur and polysulfides. Here, pillaring the multilayer graphene membrane with a metal-organic framework (MOF) demonstrates the substantial impact of a versatile interlayer design in tackling these issues. Unlike regular composite separators reported so far, the participation of tri-metallic Ni-Co-Mn MOF as pillars supports the construction of an ion-channel interconnected interlayer structure, unexpectedly balancing the interfacial concentration polarization, spatially confining the soluble polysulfides, and vastly affording the lithiophilic sites for highly efficient polysulfide sieving/conversion. As a demonstration, we show that the MOF-pillared interlayer structure enables outstanding capacity (1634 mAh g-1 at 0.1 C) and longevity (average capacity decay of 0.034 % per cycle in 2000 cycles) for lithium-sulfur batteries. Besides, the multilayer separator can be readily integrated into the high-nickel cathode (LiNi0.91Mn0.03Co0.06O2)-based lithium-ion batteries, which efficiently suppresses the undesired phase evolution upon cycling. These findings suggest the potential of "gap-filling" materials in fabricating multi-functional separators, bringing forward the pillared interlayer structure for energy-storage applications.

Comparison of In Situ and Postsynthetic Formation of MOF-Carbon Composites as Electrocatalysts for the Alkaline Oxygen Evolution Reaction (OER)

Mixed-metal nickel-iron, NixFe materials draw attention as affordable earth-abundant electrocatalysts for the oxygen evolution reaction (OER). Here, nickel and mixed-metal nickel-iron metal-organic framework (MOF) composites with the carbon materials ketjenblack (KB) or carbon nanotubes (CNT) were synthesized in situ in a one-pot solvothermal reaction. As a direct comparison to these in situ synthesized composites, the neat MOFs were postsynthetically mixed by grinding with KB or CNT, to generate physical mixture composites. The in situ and postsynthetic MOF/carbon samples were comparatively tested as (pre-)catalysts for the OER, and most of them outperformed the RuO2 benchmark. Depending on the carbon material and metal ratio, the in situ or postsynthetic composites performed better, showing that the method to generate the composite can influence the OER activity. The best material Ni5Fe-CNT was synthesized in situ and achieved an overpotential (η) of 301 mV (RuO2η = 354 mV), a Tafel slope (b) of 58 mV/dec (RuO2b = 91 mV/dec), a charge transfer resistance (Rct) of 7 Ω (RuO2 Rct = 39 Ω), and a faradaic efficiency (FE) of 95% (RuO2 FE = 91%). Structural changes in the materials could be seen through a stability test in the alkaline electrolyte, and chronopotentiometry over 12 h showed that the derived electrocatalysts and RuO2 have good stability.

Metal-Organic Frameworks for Enhanced Hydrogen Generation from Syngas: A Density Functional Theory Approach

Although methane poses environmental concerns, it is employed in hydrogen production processes such as steam-methane reforming (SMR), which has an issue of by-products released. Initiatives are being pursued to address CO and CO2 emissions using carbon capture methods, with the goal of minimizing environmental harm while improving pure hydrogen generation from syngas. In this study, porous coordination network (PCN-250) has been studied for its selective adsorption property towards CO, CO2 and H2O as syngas mixture to obtain pure hydrogen. For this purpose, the trimetallic cluster node Fe2M (where Fe2 represents the 3+ oxidation state and M is Cr(II), Mn(II), Fe(II), Co(II), Ni(II), and Zn(II)) has been considered. Fe(III) in combination with metal atoms like Cr(II), Co(II), or Ni(II) has been found to exhibit enhanced adsorption properties towards CO, CO2 and H2O. The molecule with the strongest interaction was found to be H2O over Fe(III)2Zn(II) cluster and weakest interaction was found between H2 and Fe(III)2Ni(II). Charge transfer, natural bond orbital (NBO) and spin density analyses reveal the electronic structural properties of this combination, leading to enhanced adsorption of CO and CO2.

In-situ integrated electrodes of FeM-MIL-88/CP for simultaneous ultra-sensitive detection of dopamine and acetaminophen based on crystal engineering strategy

Designing and exploiting integrated electrodes is the current inevitable trend to realize the sustainable development of electrochemical sensors. In this work, a series of integrated electrodes prepared by in situ growing the second metal ion-modulated FeM-MIL-88 (M = Mn, Co and Ni) on carbon paper (CP) (FeM-MIL-88/CP) were constructed as the electrochemical sensing platforms for the simultaneous detection of dopamine (DA) and acetaminophen (AC). Among them, FeMn-MIL-88/CP exhibited the best sensing behaviors and achieved the trace detection for DA and AC owing to synergistic catalysis between Fe3+, Mn2+ and CP. The electrochemical sensor based on FeMn-MIL-88/CP showed ultra-high sensitivities of 2.85 and 7.46 μA μM-1 cm-2 and extremely low detection limits of 0.082 and 0.015 μM for DA and AC, respectively. The FeMn-MIL-88/CP also exhibited outstanding anti-interference ability, repeatability and stability, and satisfactory results were also obtained in the detection of actual samples. The mechanism of Mn2+ modulation on the electrocatalytic activity of FeMn-MIL-88/CP towards DA and AC was revealed for the first time through the density functional theory (DFT) calculations. Good adsorption energy and rapid electron transfer worked synergistically to improve the sensing performances of DA and AC. This work not only provided a high-performance integrated electrode for the sensing field, but also demonstrated the influencing factors of electrochemical sensing at the molecular levels, laying a theoretical foundation for the sustainable development of subsequent electrochemical sensing.

A Family of Cagelike Mn-Silsesquioxane/Bathophenanthroline Complexes: Synthesis, Structure, and Catalytic and Antifungal Activity

This study reports a novel family of cage manganesesilsesquioxanes prepared via complexation with bathophenanthroline (4,7-diphenyl-1,10-phenanthroline). The resulting Mn4-, Mn6Li2-, and Mn4Na-compounds exhibit several unprecedented cage metallasilsesquioxane structural features, including intriguing self-assembly of silsesquioxane ligands. Complexes were tested in vitro for fungicidal activity against seven classes of phytopathogenic fungi. The representative Mn4Na-complex acts as a catalyst in the cycloaddition of CO2 to epoxides under solvent-free conditions to form cyclic carbonates in good yields.

Carbon nanotube-decorated hierarchical porous nickel/carbon hybrid derived from nickel-based metal-organic framework for enhanced methyl blue adsorption

This work reports the incorporation of coordinated water into Ni-BTC nanorods (Ni-BTC-O) which induces their structural transformation to Ni-BTC nanofibres (Ni-BTC-F). The carbonization of the Ni-BTC nanofibres at 600 °C results in the formation of carbon nanotube (CNT)-decorated hierarchical porous nickel/carbon hybrid (labelled as Ni/C-600) with enlarged pores. In contrast, the Ni/C hybrid obtained from the carbonization of the original (unmodified) Ni-BTC nanorods (Ni-BTC-O) at 600 °C (labelled as Ni-BTC-O-600) exhibits smaller pore size and does not show the formation of CNTs. The Ni/C-600 hybrid derived from Ni-BTC-F shows a very high adsorption capacity of 686.8 mg g^-1 toward methyl blue (MB) dye. This is approximately 4.8 times higher than the adsorption capacity of Ni-BTC-O-600 (144.1 mg g^-1). The higher adsorption performance of Ni/C-600 relative to Ni-BTC-O-600 can be attributed to its larger pore volume, hierarchical porosity, and additional adsorption sites provided by the CNTs. In addition, the Ni/C-600 hybrid can maintain 90% of its adsorption capacity after 5 consecutive cycles, demonstrating its potential as an efficient and recyclable adsorbent for MB dye.

Enhanced selective copper precipitation by mechanochemically activated benzene tricarboxylic acid

Toward the treatment of waste solution containing heavy metals, direct precipitation of the metal ions from an acidic solution without alkaline neutralisation is still the greatest challenge. Based on the ligand properties of benzene tricarboxylic acid (BTC) to copper ions, a simple ball milling with 90 min at 400 rpm was used to activate BTC to enhance its capacity for copper removal from the pH of the original solution around 3-4. A set of analytical methods were used to characterise the activated BTC sample and BTC-Cu precipitate before and after copper precipitation. Compared with the raw BTC, the activated BTC could efficiently remove copper ions over 90% from an initial copper concentration of 100 mg/L in a shorter time from an acidic media with lower pH of around 2.60 and the maximum adsorption capacity can be stable at about 111.70 mg/g, resulting from probably the enhanced deprotonation effect for copper incorporation. Furthermore, at controlled dosage, the activated BTC demonstrated much high selectivity on precipitating copper ions from other heavy metals of Ni, Mn, Zn and Cd and provided a new approach for easy copper recycling from waste solution as secondary sources. This process may serve the purpose of recycling both metal and acidic solutions after the purification.

Functionalized β-Cyclodextrins Catalyzed Environment-Friendly Cycloaddition of Carbon Dioxide and Epoxides

Ammonium, imidazole, or pyridinium functionalized β-cyclodextrins (β-CDs) were used as efficient one-component bifunctional catalysts for the coupling reaction of carbon dioxide (CO₂) and epoxide without the addition of solvent and metal. The influence of different catalysts and reaction parameters on the catalytic performance were examined in detail. Under optimal conditions, Im-CD1-I catalysts functionalized with imidazole groups were able to convert various epoxides into target products with high selectivity and good conversion rates. The one-component bifunctional catalysts can also be recovered easily by filtration and reused at least for five times with only slight decrease in catalytic performance. Finally, a possible process for hydroxyl group-assisted ring-opening of epoxide and functionalized group- induced activation of CO₂ was presented.

High yield M-BTC type MOFs as precursors to prepare N-doped carbon as peroxymonosulfate activator for removing sulfamethazine: The formation mechanism of surface-bound SO4•- on Co-Nx site

M-BTCs (M = Fe, Co and Mn)/melamine were used to prepare N-doped carbon materials, and their performances as activator of peroxymonosulfate (PMS) for sulfamethazine (SMZ) removal were compared. M-BTC type metal-organic frameworks (MOFs) were synthesized under room temperature, with their yield about 7.5 times of ZIF-67 which is the most used MOFs to prepare N-doped carbon materials as the catalyst of persulfate-based advanced oxidation processes. Co-BTC/melamine derived N-doped carbon materials (Co-BTC/5MNC) performed the best, even better than that of ZIF-67 derived N-doped carbon materials. Initial pH (3-9), 0-10 mM inorganic anions (Cl^-, NO₃^-, HCO₃^- and H₂PO₄^2-) and humic acid (5 and 10 mg/L) had no obvious inhibition on SMZ removal with Co-BTC/5MNC as catalyst. The results of both X-ray photoelectron spectroscopy and density functional theory (DFT) calculations indicated that N-coordinated cobalt single atom site (Co-N_x) was the possible active site of Co-BTC/5MNC. Importantly, surface-bound SO₄^•- was identified as the dominant reactive oxygen species for SMZ removal. The SO₄^•- generated through the charge transfer between PMS and catalyst, and was tightly adsorbed on Co-N_x site.

Nickel-Based Metal-Organic Frameworks as Electrocatalysts for the Oxygen Evolution Reaction (OER)

The exploration of earth-abundant electrocatalysts with high performance for the oxygen evolution reaction (OER) is eminently desirable and remains a significant challenge. The composite of the metal-organic framework (MOF) Ni₁₀Co-BTC (BTC = 1,3,5-benzenetricarboxylate) and the highly conductive carbon material ketjenblack (KB) could be easily obtained from the MOF synthesis in the presence of KB in a one-step solvothermal reaction. The composite and the pristine MOF perform better than commercially available Ni/NiO nanoparticles under the same conditions for the OER. Activation of the nickel-cobalt clusters from the MOF can be seen under the applied anodic potential, which steadily boosts the OER performance. Ni₁₀Co-BTC and Ni₁₀Co-BTC/KB are used as sacrificial agents and undergo structural changes during electrochemical measurements, the stabilized materials show good OER performances.

Selective photocatalytic oxidation of cyclohexene coupled with hydrogen evolution from water splitting over Ni/NiO/CdS and mechanism insight

The reaction process of photocatalytic oxidation of cyclohexene including the oxidation products and oxidation active substance.

Synergetic effect of ZnCo2O4/inorganic salt as a sustainable catalyst system for CO2 utilization

Currently, it is essential to consider the rapidly increasing emission of CO₂ into the atmosphere, causing major environmental issues such as climate change and global warming. In this work, we have developed the binary catalyst system (ZnCo₂O₄/inorganic salt) for chemical fixation of CO₂ with epoxides into cyclic carbonates without solvent, and all reactions were performed on a large scale using a 100 ml batch reactor. Two mesoporous catalysts of ZnCo₂O₄ with different architecture, such as flakes (ZnCo-F) and spheres (ZnCo-S) were synthesized and utilized as a heterogeneous catalyst for cycloaddition reaction. The bifunctional property of catalysts is mainly attributed to strong acidic and basic properties confirmed by TPD (NH₃ & CO₂) analysis. The ZnCo-F catalyst exhibited excellent conversion of propylene oxide (99.9%) with good corresponding selectivity of propylene carbonate (≥99%) in the presence of inorganic salt (KI) at 120 °C, 2 MPa, 3 h. In addition, ZnCo-F catalyst demonstrated good catalytic applicability towards the various substrates scope of the epoxide. Furthermore, the catalytic properties were examined by evaluating the reaction parameter such as catalyst loading, pressure, temperature and time. The proposed catalyst exhibited good reusability for cycloaddition reaction without significant change in its catalytic activity and proposed a possible reaction mechanism for chemical fixation of CO₂ with epoxide into cyclic carbonate over ZnCo-F/KI.

Study on Selected Metal-Organic Framework-Based Catalysts for Cycloaddition Reaction of CO2 with Epoxides: A Highly Economic Solution for Carbon Capture and Utilization

The level of carbon dioxide in the atmosphere is growing rapidly due to fossil fuel combustion processes, heavy oil, coal, oil shelter, and exhausts from automobiles for energy generation, which lead to depletion of the ozone layer and consequently result in global warming. The realization of a carbon-neutral environment is the main focus of science and academic researchers of today. Several processes were employed to minimize carbon dioxide in the air, some of which include the utilization of non-fossil sources of energy like solar, nuclear, and biomass-based fuels. Consequently, these sources were reported to have a relatively high cost of production and maintenance. The applications of both homogeneous and heterogeneous processes in carbon capture and storage were investigated in recent years and the focus now is on the conversion of CO2 into useful chemicals and compounds. It was established that CO2 can undergo cycloaddition reaction with epoxides under the influence of special catalysts to give cyclic carbonates, which can be used as value-added chemicals at a different level of pharmaceutical and industrial applications. Among the various catalysts studied for this reaction, metal-organic frameworks are now on the frontline as a potential catalyst due to their special features and easy synthesis. Several metal-organic framework (MOF)-based catalysts were studied for their application in transforming CO2 to organic carbonates using epoxides. Here, we report some recent studies of porous MOF materials and an in-depth discussion of two repeatedly used metal-organic frameworks as a catalyst in the conversion of CO2 to organic carbonates.

Bimetallic Ag-Zn-BTC/GO composite as highly efficient photocatalyst in the photocatalytic degradation of reactive yellow 145 dye in water

Ag_x-Zn_100-x-BTC/GO composites (BTC: benzene-1,3,5-tricarboxylic, GO: graphene oxide) with different Ag/Zn molar ratios were synthesized using microwave-assisted hydrothermal treatment. The Ag_x-Zn_100-x-BTC/GO exhibited excellent photocatalytic performance in the reactive yellow 145 dye (RY-145) degradation under irradiation of visible light with nearly 100% of RY-145 removal after 35 min, as compared to Zn-BTC/GO and Ag-BTC/GO. Reactive oxygen species scavenging assays have shown that the holes (h⁺) and superoxide radical anion (O₂^-•) play a primary role in RY-145 degradation. Based on the band structure of materials, the Z-scheme photocatalytic mechanism was suggested. The effect of catalyst dosage, pH and dye concentration on the efficiency of photocatalytic activity of bimetallic Ag₅₀-Zn₅₀-BTC/GO was also investigated. The improvement in photocatalytic activity of bimetallic Ag₅₀-Zn₅₀-BTC/GO could be given by the synergism of (i) absorption of visible light confirmed by UV-Vis diffuse reflectance spectra; (ii) the increased lifetime as evidenced by photoluminescence spectra and transient photocurrent response; (iii) the increased oxygen vacancy defects as confirmed by X-ray photoelectron spectroscopy results. The degradation pathway of RY-145 dye was also predicted based on liquid chromatography-mass spectrometer analysis. The removed chemical oxygen demand, biological oxygen demand, total organic carbon outcomes indicated the high mineralization ability for RY-145 degradation over Ag₅₀-Zn₅₀-BTC/GO.

Metal organic framework derived NaCoxOy for room temperature hydrogen sulfide removal

Novel NaCoxOy adsorbents were fabricated by air calcination of (Na,Co)-organic frameworks at 700 °C. The NaCoxOy crystallized as hexagonal microsheets of 100-200 nm thickness with the presence of some polyhedral nanocrystals. The surface area was in the range of 1.15-1.90 m2 g-1. X-ray photoelectron spectroscopy (XPS) analysis confirmed Co2+ and Co3+ sites in MOFs, which were preserved in NaCoxOy. The synthesized adsorbents were studied for room-temperature H2S removal in both dry and moist conditions. NaCoxOy adsorbents were found ~ 80 times better than the MOF precursors. The maximum adsorption capacity of 168.2 mg g-1 was recorded for a 500 ppm H2S concentration flowing at a rate of 0.1 L min-1. The adsorption capacity decreased in the moist condition due to the competitive nature of water molecules for the H2S-binding sites. The PXRD analysis predicted Co3S4, CoSO4, Co3O4, and Co(OH)2 in the H2S-exposed sample. The XPS analysis confirmed the formation of sulfide, sulfur, and sulfate as the products of H2S oxidation at room temperature. The work reported here is the first study on the use of NaCoxOy type materials for H2S remediation.

Determination of halogenated hydrocarbons in urine samples using a needle trap device packed with Ni/Zn-BTC bi-MMOF via the dynamic headspace method

In this study, a nickel/zinc-BTC bi-metallic metal-organic framework (bi-MMOF) was employed as a new and efficient adsorbent in a needle trap device (NTD) for headspace (HS) sampling, extraction and analysis of halogenated hydrocarbons (trichloroethylene, tetrachloroethylene, chloroform, and tetrachloroethylene) from spiked and real urine samples. Characterization of the prepared adsorbent was accomplished by FT-IR, PXRD, EDX, elemental mapping, and FE-SEM techniques. According to experimental results, the optimal temperature and extraction time, salt content, temperature and desorption time of the response surface methodology (RSM) and Box-Behnken design (BBD) were determined to be 56 °C and 30 min, 5.5%, 350 °C and 8 min for the studied halogenated hydrocarbons, respectively. The calculated values of detection limit and quantitation limit parameters were in the range of 1.02-1.10 and 2.01-2.4.0 ng L-1, respectively. Moreover, intermediate precision and repeatability of the method were in the range of 4.90-8.20% and 1.50-4.80%, respectively. The recovery percentages of analytes were obtained to be in the range of 95.0-97.0% 10 days after the sampling and storage at 4 °C. This study showed that the proposed HS-NTD:Ni/Zn-BTC method coupled with a GC-FID can be employed as a simple, fast, and sensitive procedure for non-metabolized halogenated hydrocarbons from urine samples in biological monitoring.

Selective and Fast Detection of Fluoride-Contaminated Water Based on a Novel Salen-Co-MOF Chemosensor

The development of selective and fast optical sensitive chemosensors for the detection and recognition of different cations and anions in a domain is still a challenge in biological, industrial, and environmental fields. Herein, we report a novel approach for the detection and determination of fluoride ion (F-) sensing based on a salen-cobalt metal-organic framework (Co(II)-MOF). By a simple method, the Co(II)-MOF was synthesized and characterized using several tools to elucidate the structure and morphology. The photoluminescence (PL) spectrum of the Co(II)-MOF (100.0 nM/L) was examined versus different ionic species like F-, Br-, Cl-, I-, SO4 2-, and NO3 - and some cationic species like Mg2+, Ca2+, Na+, and K+. In the case of F- ions, the PL intensity of the Co(II)-MOF was scientifically enhanced with a remarkable red shift. With the increase of F- concentration, the Co(II)-MOF PL emission spectrum was also professionally enhanced. The limit of detection (LOD) for the Co(II)-MOF chemosensor was 0.24 μg/L, while the limit of quantification (LOQ) was 0.72 μg/L. Moreover, a comparison of the Co(II)-MOF optical approach with other published reports was studied, and the mechanism of interaction was also investigated. Additionally, the applicability of the current Co(II)-MOF approach in different real water samples, such as tap water, drinking water, Nile River water, and wastewater, was extended. This easy-to-use future sensor provides reliable detection of F- in everyday applications for nonexpert users, especially in remote rural areas.

A facile fabrication of a multi-functional and hierarchical Zn-based MOF as an efficient catalyst for CO2 fixation at room-temperature

Multi-functional and hierarchical Zn-MOF was rapidly synthesized by room-temperature stirring using an organic amine as a protonation agent and exhibited remarkable improvement for CO₂ cycloaddition to bulky epoxides.

Investigation on Electroreduction of CO2 to Formic Acid Using Cu3(BTC)2 Metal-Organic Framework (Cu-MOF) and Graphene Oxide

A recent class of porous materials, viz., metal-organic frameworks (MOFs), finds applications in several areas. In this work, Cu-based MOFs (Cu-benzene-1,3,5-tricarboxylic acid) along with graphene oxide, viz., Cu-MOF/GO, are synthesized and used further for reducing CO2 electrochemically. The reduction was accomplished in various supporting electrolytes, viz., KHCO3/H2O, tetrabutylammonium bromide (TBAB)/dimethylformamide (DMF), KBr/CH3OH, CH3COOK/CH3OH, TBAB/CH3OH, and tetrabutylammonium perchlorate (TBAP)/CH3OH to know their effect on product formation. The electrode fabricated with the synthesized material was used for testing the electroreduction of CO2 at various polarization potentials. The electrochemical reduction of CO2 is carried out via the polarization technique within the experimented potential regime vs saturated calomel electrode (SCE). Ion chromatography was employed for the analysis of the produced products in the electrolyte, and the results showed that HCOOH was the main product formed through reduction. The highest concentrations of HCOOH formed for different electrolytes are 0.1404 mM (-0.1 V), 66.57 mM (-0.6 V), 0.2690 mM (-0.5 V), 0.2390 mM (-0.5 V), 0.7784 mM (-0.4 V), and 0.3050 mM (-0.45 V) in various supporting electrolyte systems, viz., KHCO3/H2O, TBAB/DMF, KBr/CH3OH, CH3COOK/CH3OH, TBAB/CH3OH, and TBAP/CH3OH, respectively. The developed catalyst accomplished a significant efficiency in the conversion and reduction of CO2. A high faradic efficiency of 58% was obtained with 0.1 M TBAB/DMF electrolyte, whereas for Cu-MOF alone, the efficiency was 38%. Thus, the work is carried out using a cost-effective catalyst for the conversion of CO2 to formic acid than using the commercial electrodes. The synergistic effect of GO sheets at 3 wt % concentration and Cu+OH- interaction leads to the formation of formic acid in various electrolytes.

Chemical fixation of CO2 into cyclic carbonates catalyzed by bimetal mixed MOFs: the role of the interaction between Co and Zn

Catalytic conversion of carbon dioxide into cyclic carbonates in the presence of bimetal mixed MOFs.

Dual hydrogen-bond donor group-containing Zn-MOF for the highly effective coupling of CO2 and epoxides under mild and solvent-free conditions

A novel 3D Zn₃(L)₃(H₂L) MOF with dual hydrogen-bond donor (HBD) groups exhibited an efficient catalytic performance for the CO₂ cycloaddition with epoxides under 80 °C, 1.0 MPa and solvent-free conditions.

Immobilized BiCl3@Bi@g-C3N4 on one-dimensional multi-channel carbon fibers as heterogeneous catalyst for efficient CO2 cycloaddition reaction

A novel heterogeneous catalyst (BBCNC), where the Bi, BiCl₃ and g-C₃N₄ were deposited on one-dimensional multi-channel carbon fibers (CNFs), was developed and characterized.

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.