Three-component NiO/Fe₃O₄/rGO nanostructure as an electrode material towards supercapacitor and alcohol...

A nanocomposite made of nickel oxide and iron oxide (NiO/Fe₃O₄) and its hybrid with reduced graphene oxide (rGO) as a conductive substrate with a highly functional surface (NiO/Fe₃O₄/rGO) was synthesized using a simple hydrothermal approach. This study addresses the challenge of developing efficient materials for energy storage and alcohol fuel cells. After confirming the synthesis through structural analysis, the potential of these nanocomposites as supercapacitor electrodes and catalysts for methanol and ethanol oxidation in alcohol fuel cells were evaluated. The synergy of combining the two metal oxides and adding rGO to the composite structure led to excellent electrocatalytic activity in alcohol oxidation. For the modified NiO/Fe₃O₄/rGO electrode in the methanol oxidation reaction (MOR), a current density of 450 mA/cm² at 0.67 V and excellent catalyst stability of 98.7 % over 20 h in chronoamperometric analysis were observed. In the ethanol oxidation reaction (EOR), an oxidative current of 235 mA/cm² at a peak potential of 0.76 V was seen, with catalyst stability of 96.4 % after 20 h. As a supercapacitor electrode, the NiO/Fe₃O₄ composite demonstrated a specific capacitance of 946 F/g, while NiO/Fe₃O₄/rGO showed 1155 F/g. The stability of these electrodes after 10000 GCD cycles was 83.6 % and 90.6 %, respectively. These findings suggest that the proposed structures are cost-effective and reliable alternatives for energy storage and production, suitable for alcohol fuel cells and supercapacitors.