“…Mushrooming energy demand, coupled with concerns over fossil fuel depletion and greenhouse gas emissions, has spurred the exploration of clean energy technologies for efficient conversion and storage. 1,2 Among the novel clean energy technologies, rechargeable metal–air batteries 3–5 and water electrolysis, 6–8 which involve the oxygen evolution reaction (OER), have attracted an amount of attention because of their superior simplicity, reliability and non-polluting properties. 9–13 However, the slow kinetics and high overpotential greatly confine the OER, leading to considerable loss of energy during the reaction.…”