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It is common to use efficient catalysts in the anodes and cathodes of methanol and ethanol fuel cells, such as platinum and ruthenium. However, due to their expansivity and rarity, finding a suitable alternative is important. In this work, multi-component catalysts consisting of tungsten oxide, nickel cobaltite, and activated carbon were synthesized through the hydrothermal method. The performance of catalysts in the processes of methanol and ethanol oxidation reactions (MOR and EOR) were investigated. The addition of activated carbon obtained from wheat husk, with an excellent active surface and acceptable electrical conductivity, to the matrix of the catalyst significantly facilitated the oxidation process of alcohols and enhanced the efficiency of the catalyst. The physical and electrochemical characterization of the NiCo2O4/WO3 hybridized with the wheat husk-derived activated carbon (ACWH) catalyst indicated its successful synthesis and good performance in the alcohol oxidation process. NiCo2O4/WO3/ACWH with an oxidation current density of 63.39 mA/cm2 at the peak potential of 0.58 V (1.59 vs. RHE), a cyclic stability of 98.6% in the methanol oxidation reaction (MOR) and 27.98 mA/cm2 at the peak potential of 0.67 V (1.68 vs. RHE), and a cyclic stability of 95.7% in the ethanol oxidation reaction (EOR) process can be an interesting option for application in the anodes of alcohol fuel cells. [ABSTRACT FROM AUTHOR]

This study reveals, for the first time, the excellent capability of MnWO4-CNT as a supercapacitor electrode compared to MnWO4. In previous research conducted on this compound, RGO was used to enhance its electrochemical properties. The objective of this study is to investigate the effects of CNT on the electrochemical properties of the compound, which also yielded promising results. The physical and morphological analysis of MnWO4 and MnWO4-CNT was conducted using Raman, XRD, BET, and SEM-EDX techniques. The electrochemical performance of the samples was assessed through cyclic voltammetry (CV), impedance electrochemical spectroscopy (EIS), and galvanostatic charge–discharge (GCD). Notably, MnWO4-CNT exhibited a significant specific capacitance of 1849.14 F·g−1 at a scan rate of 10 mV·s−1. The stability evaluation of the samples demonstrated a high capacitance retention of 81.2% and 89.4% for MnWO4 and MnWO4-CNT, respectively. The substantial specific capacity, along with the favorable stability of MnWO4-CNT, positions it as a highly promising material for utilization in supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

Transition metal oxide (TMO) binary compounds have shown good performance in energy devices. Therefore, the present study investigates the performance of hydrothermally synthesized cobalt molybdate (CoMoO4) with a flower-like morphology for electrodes in supercapacitors and methanol oxidation reaction (MOR). The morphology and microstructure were examined using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy-dispersive spectroscope (EDS) mapping. Cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) were analyzed to examine the potential of nanocomposites for supercapacitor electrodes. The results showed the specific capacitance of 243 F/g in a 6 M KOH solution with a stability of 82% after 2000 cycles. The MOR investigation of the synthesized electrode suggested a suitable trend for methanol oxidation at the optimal scan rate and concentration. As a result, CoMoO4 can be a relatively cost-effective option for use in supercapacitor electrodes and an attractive and inexpensive catalyst for methanol oxidation. [ABSTRACT FROM AUTHOR]

Today, finding low-cost electro-catalysts for methanol and ethanol oxidation with high performance and stability is one of the new research topics. A nanocatalyst based on metal oxides in the form of MnMoO4 was synthesized by a hydrothermal method for methanol (MOR) and ethanol (EOR) oxidation reactions. Adding reduced graphene oxide (rGO) to the catalyst structure improved the electrocatalytic activity of MnMoO4 for the oxidation processes. The crystal structure and morphology of the MnMoO4 and MnMoO4-rGO nanocatalysts were investigated by physical analyses such as scanning electron microscopy and X-ray diffraction. Their abilities for MOR and EOR processes in an alkaline medium were evaluated by performing electrochemical tests such as cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. MnMoO4-rGO showed oxidation current densities of 60.59 and 25.39 mA/cm2 and peak potentials of 0.62 and 0.67 V in MOR and EOR processes (at a scan rate of 40 mV/s), respectively. Moreover, stabilities of 91.7% in MOR and 88.6% in EOR processes were obtained from the chronoamperometry analysis within 6 h. All these features make MnMoO4-rGO a promising electrochemical catalyst for the oxidation of alcohols. [ABSTRACT FROM AUTHOR]

The demands for alternative energy have led researchers to find effective electrocatalysts in fuel cells and increase the efficiency of existing materials. This study presents new nanocatalysts based on two binary transition metal oxides (BTMOs) and their hybrid with reduced graphene oxide for methanol oxidation. Characterization of the introduced three-component composite, including cobalt manganese oxide (MnCo2O4), nickel cobalt oxide (NiCo2O4), and reduced graphene oxide (rGO) in the form of MnCo2O4/NiCo2O4/rGO (MNR), was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray (EDX) analyses. The alcohol oxidation capability of MnCo2O4/NiCo2O4 (MN) and MNR was evaluated in the methanol oxidation reaction (MOR) process. The crucial role of rGO in improving the electrocatalytic properties of catalysts stems from its large active surface area and high electrical conductivity. The alcohol oxidation tests of MN and MNR showed an adequate ability to oxidize methanol. The better performance of MNR was due to the synergistic effect of MnCo2O4/NiCo2O4 and rGO. MN and MNR nanocatalysts, with a maximum current density of 14.58 and 24.76 mA/cm2 and overvoltage of 0.6 and 0.58 V, as well as cyclic stability of 98.3% and 99.7% (at optimal methanol concentration/scan rate of 20 mV/S), respectively, can be promising and inexpensive options in the field of efficient nanocatalysts for use in methanol fuel cell anodes. [ABSTRACT FROM AUTHOR]

Co3O4 nanorods and hybrid reduced graphene oxide (Co3O4/rGO) were synthesized on a Ni foam substrate using affordable and simple hydrothermal synthesis. Then, the structural and morphological investigations of nanoparticles were carried out using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) mapping, Raman spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. It was found that rGO increased the surface and short channels for the transfer of ions and electrons. The maximum capacitance of Co3O4/rGO was found to be 2870 F/g, while Co3O4/rGO/NF was observed to have the largest capacitance in the literature. Furthermore, rGO decreased resistance arising from charge and ion transfer by creating shorter channels. Therefore, the superior Co3O4/rGO/NF electrode in the tow-electrode system was investigated for asymmetric supercapacitor purposes. The rGO electrode served as the negative electrode, while the Co3O4/rGO/NF was assumed to be the positive electrode. A discharge time of 144 s led to a capacitance of 148 F/g, a power density of 486 W/kg, and an energy density of 20 Wh/kg. [ABSTRACT FROM AUTHOR]