Boosting oxygen evolution reaction performance by nickel substituted cobalt-iron oxide nanoparticles embedded over reduced graphene oxide

Designing non-precious-metal (NPM) electrocatalysts for oxygen evolution reaction (OER) from alkaline water is of paramount importance for clean, sustainable and conversion technologies. Herein, we report a facile, scalable and rapid microwave assisted synthesis to produce Ni substituted cobalt-iron oxides Co1-xNixFe2O4 (x = 0, 0.10, 0.25, 0.50, 0.75 and 1) supported over conductive reduced graphene oxide (rGO) and successfully employing them as electrode materials for OER in alkaline medium. Interestingly, by tuning Ni amount in cobalt-iron oxide has a profound influence on the OER activity i.e., Co0.75Ni0.25Fe2O4/rGO exhibits the best OER performance with an overpotential of 440 mV at 10 mA cm(-2) and considerable electrochemical stability over 1000 cycles and even up to 10 h in 0.1 M KOH solution.