Hierarchical Urchin-like Cobalt-Doped CuO for Enhanced Electrocatalytic Oxygen Evolution Reaction

Designing an efficient, low-cost, and earth-abundant electrocatalyst for water oxidation is the center of attraction in renewable energy technology, but it is still a grand challenge. Herein, we report a simple microwave-assisted solvothermal method to synthesize cobalt-doped CuO as a noble metal-free efficient electrocatalyst for oxygen evolution reaction (OER) in an alkaline medium. Optimal cobalt doping (5%) in CuO manifests an improved OER activity with an overpotential of 120 mV, which is ∼2.66 times lower than that obtained with pristine CuO to achieve a current density of 10 mA cm–2, superior to the state-of-the-art OER catalysts. A Tafel slope of 118 mV dec–1 with an electrochemical active surface area of 40 cm2 and a charge transfer resistance of 2.58 Ω were achieved with 5% cobalt-doped CuO, which validate the role of metal doping and importance of doping in transition metal oxides to enhance the electrochemical OER activity.