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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]

Present work comprehensively investigated the electrochemical response of Nickel-2 Aminoterephthalic acid Metal–Organic Framework (NiNH2BDC) and its reduced graphitic carbon (rGO) based hybrids for methanol (CH3OH) oxidation reaction (MOR) in an alkaline environment. In a thorough analysis of a solvothermally synthesized Metal–Organic Frameworks (MOFs) and its reduced graphitic carbon-based hybrids, functional groups detection was performed by FTIR, the morphological study by SEM, crystal structure analysis via XRD, and elemental analysis through XPS while electrochemical testing was accomplished by Chronoamperometry (CA), Cyclic Voltametric method (CV), Electrochemically Active Surface Area (EASA), Tafel slope (b), Electron Impedance Spectroscopy (EIS), Mass Activity, and roughness factor. Among all the fabricated composites, NiNH2BDC MOF/5 wt% rGO hybrid by possessing an auspicious current density (j) of 267.7 mA/cm2 at 0.699 V (vs Hg/HgO), a Tafel slope value of 60.8 mV dec−1, EASA value of 15.7 cm2, and by exhibiting resistance of 13.26 Ω in a 3 M CH3OH/1 M NaOH solution displays grander electrocatalytic activity as compared to state-of-the-art platinum-based electrocatalysts. [ABSTRACT FROM AUTHOR]

In present work the development of copper benzenetricarboxylic acid metal organic framework (Cu-BTC MOF) based electrocatalyst and the effect of graphene oxide on catalytic activity of metal organic framework were studied for methanol oxidation reaction. Cu-MOF was prepared by a facile hydrothermal method and graphene oxide flakes were synthesized via improved Hummer's method. Surface morphological studies of catalyst were analyzed through scanning electron microscopy technique, which revealed cubic structure of crystals, while the crystallinity and functional groups present were characterized through X-ray Diffraction and FTIR spectroscopy respectively. Electrochemical studies were conducted by using cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry techniques. Among all series of catalyst, 5 wt% GO/Cu-MOF exhibit highest current density of 120 mA/cm2 at a scan rate value of 50 mV/s at a voltage of 0.9 V. [ABSTRACT FROM AUTHOR]

Abstract In this work the electrochemical oxidation of methanol is studied on NiO based MOFs and its composites with reduced graphene oxides. NiO-MOF and its composites were prepared through hydrothermal method. The as-prepared materials were characterized by SEM, EDX, XRD, FTIR and Raman IR for their morphological and structural properties. The activity of prepared catalyst for oxidation of methanol was tested via cyclic voltammetry (CV) in an alkaline media on glassy carbon electrode. The electrochemical performance shows the effect of rGO concentration on methanol oxidation. The electro oxidation catalyzed by NiO-MOF and NiO-MOF/rGO composites exhibits a magnificent peak current density of 275.85 mA/cm2 at 0.8 V potential with a scan rate 50 mV/s making them a potential candidate for electrocatalysis. [ABSTRACT FROM AUTHOR]

In this study, we report the comparative electrocatalytic study of commercial Pt/C with Mn-Co/C and its rGO based composites (i.e., 1–8 wt% rGO @Mn-Co/C) for methanol oxidation. Catalysts were synthesized by a two-step procedure. Firstly, via the solvothermal method, all catalysts were prepared and then pyrolyzed at 700 °C in an argon and hydrogen mixture environment. The characterization of the Mn-Co/C, 1–8 wt% rGO Mn-Co/C catalysts was accomplished by XRD, SEM, EDX, Raman, TEM, BET and XPS. The as-prepared dodecahedron morphology of the initial Mn-based ZIF-67 particles is retained, with the interconnected sheets of reduced graphene oxide after the pyrolysis in a reducing atmosphere (i.e., Ar+H 2). Among all the catalysts, the 5 wt% rGO@Mn-Co/C catalyst has shown much higher electrochemical activity (i.e., 235.24 mA/cm2) and stability than other rGO-based Mn-Co/C catalysts and also than commercial Pt/C in 1 M NaOH and 3 M CH 3 OH. The presence of support materials such as rGO and the availability of nano porous carbon with Mn and Co may contribute to the improved electrocatalytic activity of 5 wt% rGO Mn-Co/C over Mn-Co/C. With a number of beneficial features in structure, composition, and nitrogen doping level, it results in enhanced electrocatalytic activity and stability as well as methanol tolerance when benchmarked with a commercial Pt/C electrocatalyst under the same testing conditions. [Display omitted] • Mn-Co/C composites with rGO (1-8wt% rGO@Mn-Co/C) were synthesized solvothermaly at 120 °C and pyrolyzed at 700 °C. • Synthesized 1-8wt% rGO@Mn-Co/C composites were used as an electrocatalyst for MOR in alkaline media. • 5wt% rGO@Mn-Co/C composite exhibits higher catalytic activity with current density of 235.24 mA/cm2 at 50mV/sec. • Catalytic activity of 5wt% rGO@Mn-Co/C composite is compared with commercial Pt/C. • Enhanced performance is due to synergic effect of rGO and residual metallic Co and Mn nanoparticles entrapped in rGO. [ABSTRACT FROM AUTHOR]

• NiO/FeO MOF and its reduced graphene oxide based composites such as 1–5 wt% FeO/NiO MOF were solvothermaly synthesized. • Synthesized bimetallic MOF and its reduced graphene oxide based composites (1–5 wt% FeO/NiO MOF) were employed as an electro catalyst for methanol oxidation. • 4 wt% FeO/NiO MOF composite exhibit superior current density 486.14 mA/cm2 at potential of 0.85 V in 3 M CH 3 OH. • Key reason behind high catalytic activity of 4 wt% FeO/NiO MOF composite was because of synergetic effect of reduced graphene oxide and MOF catalysts. We report a novel bimetallic iron oxide/nickel oxide metal–organic framework (FeO/NiO MOF) that has been synthesized by using two different linkers; 2, 5-dihydroxy terephthalic acid (DHTA) and Pyrazine and also its composites are prepared with reduced graphene oxide from 1 to 5 wt% rGO FeO/NiO MOF and afterwards characterized via several important techniques like FTIR, XRD, SEM and EDX for examination of their morphological and structural properties. The synthesized series of bimetallic MOFs composites were later used as catalyst for methanol oxidation, tested via cyclic voltammetry (CV) in 3 M Methanol and 1 M NaOH on modified GCE. The electrochemical results illustrate that electrocatalytic response of the MOF boosts astonishingly with gradual loadings of rGO from (1–4 wt%) and among all prepared series 4 wt% rGO-FeO/NiO MOF shows the highest current density of 486.14 mA/cm2 at potential of 0.85 V with scan rate of 50 mV/cm2. This superlative response of prepared catalyst makes it a promising catalytic material for methanol oxidation in DMFC. [ABSTRACT FROM AUTHOR]

In this work a novel bimetallic nickel oxide/copper oxide metal–organic framework (NiO/CuO MOF) has been developed by using two linkers: Benzene Dicarboxylic acid (BDC) and Pyrazine. The composites of NiO/CuO MOF with different amounts of reduced graphene oxide (rGO) were synthesized through a hydrothermal method and subsequently characterized by multiple significant techniques like XRD, SEM, EDX, FTIR and Raman IR for an investigation of their structural and morphological properties. The prepared series of material was later employed for electrochemical oxidation of methanol, tested by cyclic voltammetry (CV) in basic medium on a modified glassy carbon electrode (GCE). The electrochemical response depicts that increasing concentration of rGO enhances the electrocatalytic activity of the catalyst for methanol oxidation reaction (MOR). The catalyzed oxidation reaction of methanol by NiO/CuO MOF and rGO-NiO/CuO MOF composites give a superlative current density of 437. 28 mA/cm2 at 0.9 V potential at 50 mV/s scan rate. This activity makes it a promising catalytic material for electrolysis of methanol in direct methanol fuel cell (DMFC). [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]

• Nanostructured composites Mn/Zn N C @30% rGO, Mn/Zn N C @20% rGO, Mn/Zn N C @10% rGO was synthesized. • Mn/Zn N C @30% rGO demonstrates good electrocatalytic ORR activity in alkaline aqueous electrolyte solutions. • Mn/Zn N C @30% rGO has the lowest Tafel slope overpotential for attaining superior current density. • Mn/Zn N C @30% rGO has been proven reliable for test as fuel cross-over in methanol. Future fuel cells and metal-air batteries will benefit greatly from revealing self-supported electrodes with efficient oxygen reduction reaction (ORR) activity and durability. However, noble metal catalysts are expensive and unstable, necessitating research into novel metal-organic framework (MOF)-based topologies that can catalyse oxygen reduction reactions (ORR). In this work, the synthesis of nitrogen-doped carbon (N C) is derived from zeolitic imidazolate frameworks (ZIFs) and a novel Mn-doped Zn N C@rGO is synthesized using a self-templated solvothermal method and their performance in an alkaline medium for oxygen reduction reaction (ORR) is studied. The nanostructured composite outperformed the commercial Pt/C catalyst in terms of both material resources and application efficacy. The Mn/Zn N C @30% rGO exhibit outstanding performance for ORR in KOH, with a more positive cathodic peak of 0.78 V vs RHE and an onset potential of 0.97 V vs RHE, which are characteristics that suggest the possibility of reducing ORR overpotentials. The improved electrochemical performance, small Tafel slopes and methanol tolerance are ascribed to the interdependent effect of the N -doped carbon (N C) and the Mn/Zn active sites. Novel architecture, tunable porosities, template directed growth and remarkable electrocatalytic performance of Mn-doped Zn N C@rGO make it a good aspirant for energy applications. [ABSTRACT FROM AUTHOR]