High performance graphene oxide/NiAl₂O₄ directly grown on carbon cloth hybrid for oxygen evolution reaction

Due to the lethargic kinetics, the oxygen evolution reaction (OER) requires a high anodic voltage, restricting the efficiency as well as practical applications for electrochemical water splitting. For this purpose, metal oxides (M − O) are viewed as a potential competitor in this search because of their high redox potential. Still, their low conductivity and instability are two significant barriers that must be addressed. In this study the nanocomposite of NiAl₂O₄ with graphene oxide (GO) as a highly effective and long-lasting electrocatalyst for OER has been fabricated. In an alkaline (1.0 M KOH) medium, the GO/NiAl₂O₄ responds to a very sharp overpotential of 219 mV at a current density of 10 mA/cm² and with a lower value of tafel slope (43 mV/dec) as compared to its counterparts. The GO/NiAl₂O₄ corresponds to the high stability of 18 h with retained crystal structure and morphology. For the expected prolonged OER process, we assume the active redox couple due to the presence of Ni^+2/+3 metal in NiAl₂O₄ varies periodically. Furthermore, the synergistic effect of NiAl₂O₄, combined with the GO, facilitates the dynamics of O₂ evolution as a final product, and are useful for further applications in future era.