Inverse spinel Fe-NiCo2O4/NiO nanocomposite supported on defect-rich P-rGO sheets for enhanced OER activity

Abstract

Developing affordable, stable, and non-toxic electrocatalysts with strong catalytic activity is essential for commercializing hydrogen fuel economy. Here, we have developed an inverse spinel-based 0.3Fe-NiCo_1.7O₄/NiO@P-rGO electrocatalyst by solvothermal synthesis, annealing, and ultrasonication. The material's structure, phase and defects were determined using XRD and Raman analysis. TEM and FESEM investigations confirmed the material's nanoparticle-adorned urchin-shaped morphology. The elemental analysis confirmed the elemental percentages using EDX to align with the synthesized material's stoichiometric ratio. The XPS study demonstrates that the electronic environment of the nanocomposite is altered due to Fe-doping and the introduction of defect-rich P-rGO sheets. Oxygen vacancy sites are increased, and transition metal oxidation states are altered due to their synergistic modulation impact. Increased electron movement and decreased surface absorption energy are two benefits of the higher oxygen vacancy level. Due to these features, the material can attain an extremely low overpotential for OER electrocatalysis of 293 mV at 10 mA.cm^-2. Faster reaction kinetics are also suggested by the extremely low Tafel slope of 61.55 mV.dec^-1. According to the ECSA study, each active site's improved internal activity is primarily responsible for the material's better performance. Even after 24 hours of chronoamperometry testing, the material maintained a tiny overpotential of 365 mV at 10 mA.cm^-2. This work reveals that the modified 0.3Fe-NiCo_1.7O₄/NiO@P-rGO electrocatalyst may be employed as a stable anode material for hydrogen fuel production.