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In response to the escalating environmental impact of fossil fuels, there's a growing demand for clean energy solutions, particularly efficient metal-air batteries. Metal-air batteries are promising for energy storage, boasting abundant materials and low cost. However, their efficiency is hindered by slow oxygen reduction and evolution reactions. Synthesizing effective and stable oxygen electrocatalysts is crucial for enhancing battery performance. Here, this work used a simple solvothermal method to synthesize Iron–Cobalt metal-organic framework (FeCo-MOF), Manganese–Iron–Cobalt metal-organic framework (MnFeCo-MOF), and their composites with (1, 3, and 5) wt% rGO and characterized via using XRD, SEM, FTIR, and Raman spectroscopy. Electrochemical testing was conducted in 1 M KOH solution for both OER and ORR. The 3 wt% rGO MnFeCo-MOF shown the lowest overpotential of 54 mV at 10 mA/cm2 and the lowest Tafel slope of 63.4 mV/dec, with highest current density of 79.42 mA/cm2 at 25 mV/s scan rate for OER indicating excellent electrocatalytic activity superior to already reported in literature due to synergistic effect of Mn, Fe, Co, and rGO facilitating rapid electron transfer and more active sites. The 3 wt% rGO MnFeCo-MOF exhibited the halfwave potential of 0.74 V for ORR showing excellent activity comparable to commercial catalysts Pt/C. The lower potential gap ΔE 0.66 V from the overall combined plot of OER/ORR shows efficient and stable bifunctional activity of the 3 wt% rGO MnFeCo-MOF. These exceptional electrocatalytic properties pave the way for future advancements in metal-air batteries. [Display omitted] • FeCo-MOF, MnFeCo-MOF, and their composites with rGO were synthesized solvothermaly at 120 °C. • 3 wt% rGO MnFeCo-MOF showed lowest TAFEL slope 63.4 mV/dec and overpotential of 54 mV at 10 mA/cm2 for OER. • 3 wt% rGO MnFeCo-MOF for ORR has a halfwave potential of 0.74 V. • Exhibited excellent stability studied via chronopotentiometry experiment. • Synergic effect among rGO and Mn, Fe, Co MOF active sites. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting for sustainable hydrogen and oxygen production have shown enormous potentials. However, this method needs low‐cost and highly active catalysts. Traditional nano catalysts, while effective, have limits since their active sites are mostly restricted to the surface and edges, leaving interior surfaces unexposed in redox reactions. Single atom catalysts (SACs), which take advantage of high atom utilization and quantum size effects, have recently become appealing electrocatalysts. Strong interaction between active sites and support in SACs have considerably improved the catalytic efficiency and long‐term stability, outperforming their nano‐counterparts. This review's first section examines the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER). In the next section, SACs are categorized as noble metal, non‐noble metal, and bimetallic synergistic SACs. In addition, this review emphasizes developing methodologies for effective SAC design, such as mass loading optimization, electrical structure modulation, and the critical role of support materials. Finally, Carbon‐based materials and metal oxides are being explored as possible supports for SACs. Importantly, for the first time, this review opens a discussion on waste‐derived supports for single atom catalysts used in electrochemical reactions, providing a cost‐effective dimension to this vibrant research field. The well‐known design techniques discussed here may help in development of electrocatalysts for effective water splitting. [ABSTRACT FROM AUTHOR]

Summary: The human craving for energy is continually mounting and becoming progressively difficult to Gratify. At present, the world's massive energy demands are chiefly encountered by nonrenewable and benign fossil fuels. However, the development of dynamic energy cradles for a gradually thriving world to lessen fossil fuel reserve depletion and environmental concerns are persistent issues for society at present. The discovery of copious nonconventional resources to fill the gap between energy petition and supply is the extreme obligation of the modern era. A new emergent, clean, and robust alternate of fossil fuels are the fuel cells. Among the different types of fuel cells, direct methanol fuel cells are an outstanding option for light‐duty vehicles and portable devices. A critical tactic for striving and sustainable energy sources is the production of highly proficient, economical, and green catalysts for energy storage and conversion devices. Up till now a broad range of research work is available to use Pt and modify Pt‐based electrocatalysts to augment the CH3OH oxidation process. Platinum‐based nanocubes, nanorods, nanoflower, hybrids of Pt with metal‐oxides such as Fe2O3, TiO2, SnO2, MnO, Cu2O, ZnO, and with conducting polymers are extensively utilized in both acidic and basic media. Moreover, Pd‐based materials, transition metal‐based materials as well as MOF and MOF‐derived materials are also the point of interest for researchers nowadays. However, the problem associated with their practical applications is that they can be effectively employed in basic media due to comparative less stability in acidic medium. This review article will deliver a broad vision of the current progress of the MOR process concerning noble metals, transition metals, and MOF‐based materials. [ABSTRACT FROM AUTHOR]

Summary: A significant interest in the exploration of clean and renewable alternative energy resources has been observed in recent years to combat environmental pollution and energy shortages for a sustainable future. In this regard, hydrogen is clean, energy‐rich fuel with unlimited potential. It can be produced via water‐splitting process using the most abundant resources on earth, that is, water and solar/electrical energy. Metal‐organic frameworks (MOFs) are a category of porous crystalline materials with well‐organized structures and unique catalytic, optical, and electrical properties. MOFs and MOF‐derived materials have proved to be excellent catalysts for water‐splitting both by electrochemical and photoelectrochemical (PEC) routes. Furthermore, photochemical and electrochemical capabilities of these MOFs can be fine‐tuned to maximize their performance by modification in the bandgap, surface area, current density, electrochemical active surface area, and overpotential, through tailoring of the organic ligands and/or metal centers. A number of works have been dedicated to this quest resulting in promising and very effective results. Such as for photoelectrocatalysis, a composite nanorod array of TiO2/Co‐MOF acting as photoanode achieved one of the highest photocurrent densities of 2.93 mA/cm2 at 1.23 V (vs reverse hydrogen electrode [RHE]). In another study, MOF‐derived Co3C‐3/TiO2 photoanode attained the photocurrent density of 2.6 mA/cm2 at 1.23 V vs RHE. For electrocatalysis, Fe2O3/Ni‐MOF‐74 exhibited oxygen evolution reaction overpotential of 264 mV to reach 10 mA/cm2 of current density with a low Tafel plot of 48 mV/dec. Another novel material derived from MOF, MoO2‐PC‐rGO displayed a Tafel Plot of 41 mV/dec. Even though this field is in its infancy phase, it is attracting increased attention for promising results suggesting extraordinary potential for practical applications. Focus of this review article is on the overview of the development of MOFs for application in electrocatalytic and photoelectrocatalytic water‐splitting for hydrogen production. This review intends to provide a timely reference and insight for the advancement in catalysts based on MOFs for practical electrochemical and PEC water‐splitting in a clear and comprehensive manner. Starting with the brief introduction, fundamentals, factors affecting catalytic efficiency and evaluation parameters of water‐splitting are summarized followed by synthesis strategies and recent progress made by MOF‐based catalysts for PEC and electrochemical water‐splitting. [ABSTRACT FROM AUTHOR]

A considerable concern in exploring clean, efficient, and renewable energy resources to effectively replace fossil fuels and to combat the environmental problems and energy scarcities for a sustainable future has been observed. In this context, hydrogen is a clean, renewable, energetically efficient fuel with infinite potential for the future, which can generate a large amount of energy through the electrocatalytic splitting of earth‐abundant water resources. Noble metals, owing to their extraordinary efficiency and stability, are state‐of‐the‐art catalysts for the oxygen evolution reaction (OER) process. However, their scarcity and high cost hamper their commercialization. To replace these expensive noble‐metal‐based materials, researchers are extensively working on the development of cost effective, stable, conductive, and efficient non‐noble metal based materials such as transition metal oxides, borides, nitrides, sulfides, phosphides, selenides, perovskites oxides, and layered double hydroxides, where the incorporation of heteroatoms improves the electrocatalytic activity by modifying the electronic structure and enhances the conductivity and stability. In the case of transition‐metal based metal organic frameworks (MOFs) and MOF‐derived materials, the unique structure of MOFs with a high surface area and porosity, as well as rich redox chemistry of transition metals, leads to excellent response towards the OER process. Moreover, direct utilization of carbonaceous materials or making their composites with transition metals not only enhances the conductivity due to their conductive nature but also promotes stability by strongly binding with the electrocatalyst. Owing to the presence of functional groups on the surface or through different interactions, they provide multiple paths for facile electron and ion transport due to the sheet/network like structure, which help in the fine dispersion of electrocatalyst due to high surface area, prevent agglomeration, and in turn results in improved electrocatalytic activity. Besides these advances, a) there is still a need for a thorough understanding of reaction mechanism via in situ spectroscopic techniques to further optimize the composition and design of electrocatalyst to get desired results, b) the stability of the materials should be further enhanced to practically utilize synthesized material under harsh conditions without degradation, and c) the utilization of these optimized OER catalysts in a solar cell to consume solar energy (renewable energy source), remains a key requirement of the modern era. [ABSTRACT FROM AUTHOR]

This work utilized an innovative and economical remediation method to convert inexpensive waste feedstock into extremely useful catalysts. The procedure centered on polyethylene (PE), an easily accessible substance, and effectively transformed it at a mild temperature utilizing a new solvothermal technique, which entailed the reaction of sulfuric acid with PE chains at 120 °C. Throughout this process, the polymer experienced a pivotal cross-linking stage, resulting in its conversion into carbon materials when exposed to temperatures above 500 °C. To improve the catalytic characteristics, platinum (Pt) was effectively integrated into the resultant carbon matrix using the existing impregnation technique. Further, the catalyst's physicochemical properties were thoroughly analyzed utilizing SEM, FTIR, and XRD techniques. After that, the catalyst's performance was thoroughly evaluated in several electrocatalytic reactions, such as methanol oxidation, oxygen evolution and reduction reactions, and hydrogen evolution. The results of this investigation reveal the impressive electrocatalytic ability of the Pt/C catalyst made from waste plastic. It was found to be comparable to the best commercially available Pt/C catalysts in all the reactions that were examined. This research not only demonstrates the possibility of using waste plastic for catalyst production, but also serves as the first documented example, based on successfully converting waste plastic bags into Pt/C through the conventional Liquid Phase Reduction (LPR) process. This novel method has great potential for sustainable and ecologically responsible catalytic applications. • The waste plastic derived Pt/C catalyst was prepared by solvothermal method. • For MOR plastic derived Pt/C shows electrocatalytic activity of 96.74 mA/cm2 current density and 46 % stability. • For OER it attain a current density of 10 mA/cm2 at a potential of 1.65 V. • For HER achieve current density of 10 mA/cm2 at a low voltage of 39.1 mV. • For ORR it exhibits −2.80 mA cm⁻2 of current density and half potential of 0.86 V. [ABSTRACT FROM AUTHOR]

[Display omitted] • Li-air batteries have maximum theoretical energy density depending on electrolyte. • MXenes synthesis by varying etching parameters, results in unique level of quality. • Ti 3 C 2 T x composites with MOFs shows excellent OER activity and stability. • Nanocomposite supported by the Ti 3 C 2 T x MXene enhances the ORR activity. • Ti x C x-1 as cathode catalyst in LAB has good activity and Li 2 CO 3 impact is avoided. Electrocatalysis plays an important role to achieve a sustainable energy economy. Electrocatalysts enable the generation of clean fuels and feedstock of chemicals from several resources such as CO 2 , water, and nitrogen by facilitating many redox reactions in conversion systems and energy storage. The lack of readily available catalysts that meet the requirements of being economical, long-lasting, and efficient is the main biggest challenge to their widespread implementation. The MXenes, 2D new materials emerging family carries a lot of potential as electrocatalysts in MABs because of their exceptional combination of hydrophilicity, higher electrical conductivities, and tunable surface properties. Introduction to metal-air batteries, synthesis methods, MXenes properties, and MXenes electrocatalytic activities applications are described in this article, including their electrocatalytic activity in OER, HER, ORR, and as a bifunctional electrocatalyst. The prospect, challenges, and methods of increasing their electrocatalytic activities in MABs are also discussed in detail. [ABSTRACT FROM AUTHOR]

• Solvothermal synthesis and characterization of Cu-doped ZIF-8 catalysts with varying Cu+2 doping. • Electrochemical CO 2 reduction process. Cu30%ZIF-8 showed the highest current density of -40 mA cm−2 at -2.1 V vs. Ag/AgCl. • Better selectivity for CH 4 and CO compared to previous works on Cu electrodes. • High activity is due to crystalline nanostructure, sufficient Cu+2 metal sites, micro-meso dual-porosity nature and broad surface area. Electrochemical CO 2 reduction is a beneficial process for converting CO 2 into useful hydrocarbons, chemicals, and fuels. Many catalysts have been tested before for CO 2 electroreduction however achieving good stability, activity, and selectivity of the required product remains a challenge. In this work, we demonstrate the solvothermal synthesis and characterization of Cu-doped ZIF-8 catalysts with varying Cu+2 doping and applying them in the electrochemical CO 2 reduction process. Cu30%ZIF-8 showed the highest current density of -40 mA cm−2 at -2.1 V vs. Ag/AgCl and better selectivity for CH 4 and CO compared to previous works on Cu electrodes. This high activity of the Cu-doped ZIF-8 catalyst is because of the crystalline nanostructure of our catalyst with sufficient copper active metal sites and N-content, micro-meso dual-porosity nature of the structure, and broad surface area of zeolite imidazole framework to work on. [ABSTRACT FROM AUTHOR]

Cover Feature: Recent Advances in Electrocatalysis of Oxygen Evolution Reaction using Noble-Metal, Transition-Metal, and Carbon-Based Materials (ChemElectroChem 3/2021) Keywords: Electrocatalysts; Hydrogen production; Oxygen Evolution Reaction (OER); Activity parameters; Metal Organic Frameworks (MOFs) EN Electrocatalysts Hydrogen production Oxygen Evolution Reaction (OER) Activity parameters Metal Organic Frameworks (MOFs) 427 427 1 02/13/21 20210201 NES 210201 B The Cover Feature b illustrates noble-metal, transition-metal, and carbon-based compounds effectively utilized for oxygen evolution reaction electrocatalysis. Electrocatalysts, Hydrogen production, Oxygen Evolution Reaction (OER), Activity parameters, Metal Organic Frameworks (MOFs). [Extracted from the article]

This work describes electrocatalytic behavior of amiable and economical iron nickel 2-amioterephthalic acid metal organic framework (FeNiNH 2 BDC MOF) and its 2–6 wt % carbon nanotubes (CNTs) composites for oxygen evolution reaction (OER) in an alkaline media. Systematic structural and morphological analysis of solvothermally fabricated Iron (Fe) and Nickel (Ni) based MOF and their CNTs composites was carried out by Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray powder diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Brunauer–Emmett–Teller (BET) and energy dispersive X-ray spectroscopy (EDX) techniques. Synergetic effect of bimetallic metal organic framework (MOF) and conductive CNTs support improves the catalytic response of MOF. FeNiNH 2 BDC-5 wt % CNTs composite demonstrated current density of 10 mA/cm2 at an over potential (η) 0.22 V and onset potential of 1.36 V vs RHE, comparable with RuO 2 state-of-the-art catalytic material for oxygen evolution reaction in a fuel cell. Furthermore, FeNiNH 2 BDC-5 wt % CNTs composite tafel slope of 68.50mV/dec and 0.67s−1 turnover frequency (TOF) ascertain it as a promising alternative candidate towards costly Pt, Pd, Ir and Ru based catalysts. Image 1 • FeNi MOF composites with carbon nanotubes were solvothermally synthesized. • Synthesized FeNi MOF-CNTs composites were studied as electrocatalysts for OER in alkaline medium. • FeNiNH 2 BDC-5 wt % CNTs composite exhibit superior catalytic activity towards OER. • Stability retained by samples was studied via chronoamperometry experiment. • Synergetic effect between CNTs support and bimetallic MOF catalyst exist. [ABSTRACT FROM AUTHOR]

• Mo-MOF, MO/NPC and MO-MS/NPC were synthesized via solvothermal method at 200 °C and pyrolysis. • All prepared composites were characterized via SEM, TEM, FTIR, XRD and XPS. • Synthesized series is tested for methanol oxidation and for oxygen reduction reactions. • MO-MS/NPC demonstrate higher electrochemical activity such as exhibiting 354.2 mA/cm2 current density for MOR and −9.54 ma/cm2 for ORR with low overpotential value of 0.80 V. In this paper, an effective method for synthesizing three different catalysts Mo-MOF, MO/NPC, and MO-MS/NPC by solvothermal preparation and pyrolysis processes has been described. The structural and compositional characteristics of these catalysts have been thoroughly analyzed using SEM, XRD, XPS, FTIR, and TEM characterization techniques. It is noteworthy that MO-MS/NPC has proven to have remarkable electrocatalytic capabilities, exhibiting high current density i.e., 354.3 mA/cm2 and stability in methanol oxidation as well as superior electrocatalytic activity for oxygen reduction reactions Because of these qualities, MO-MS/NPC, MO/NPC, and Mo-MOF might be an attractive option as cathodic and anodic materials in direct methanol fuel cells (DMFCs). Their higher oxygen reduction abilities as cathode materials can boost the cathodic reaction's effectiveness and encourage the conversion of oxygen and protons into water, and also help methanol to oxidize into carbon dioxide at the anode, liberating electrons that can be used to produce electricity. [ABSTRACT FROM AUTHOR]

In this work the catalytic activity of cobalt based MOF and its composites with graphene oxide (GO) towards electrochemical oxidation of methanol is studied. Co-MOF-71 and its GO composites were prepared by hydrothermal method and characterized by X-ray diffraction, XPS, scanning electron microscopy and FTIR. XRD patterns revealed incorporation of GO without disturbing the crystal structure. The synthesized catalysts were tested for their electrocatalytic activity for methanol oxidation reaction (MOR) in alkaline medium. The electrochemical parameters measured with modified GCE represent the effect of graphene oxide on methanol oxidation reaction catalysed by Co-MOF-71. Co-MOF-71/GO composite showed excellent peak current density (29.1 mA/cm 2 ) at lower potential (0.1 V) and scan rate of 50 mV/s. The enhanced electrochemical activity and stability is attributed to the synergetic effect of the MOF and the GO substrate for methanol oxidation. [ABSTRACT FROM AUTHOR]