Co-Doped CuO Nanoarray: An Efficient Oxygen Evolution Reaction Electrocatalyst with Enhanced Activity

It is highly desired to enhance the catalytic activity of oxygen evolution reaction (OER) electrocatalysts made of earth-abundant elements. In this Letter, we report that the OER activity of a CuO nanoarray can be largely enhanced by Co doping. In 1.0 M KOH, the Co-CuO nanoarray on copper foam requires a current densities of 50 and 100 mA cm<sup>–2</sup> at overpotentials of only 299 and 330 mV, respectively. It also shows superior long-term durability over 15 h with a turnover frequency of 0.056 mol O<sub>2</sub> s<sup>–1</sup> at an overpotential of 300 mV.