CuCoO_x/FeOOH Core–Shell Nanowires as an Efficient Bifunctional Oxygen Evolution and Reduction Catalyst

The rational design of active and durable reversible oxygen electrocatalysts plays a key role in renewable energy conversion and storage. Here we developed copper and cobalt-based oxide/iron hydroxide hybrid nanowire arrays (CuCoO x /FeOOH) via a three-step growth–annealing–conversion approach. These hybrid nanowires offer a large surface area for electrocatalytic sites, abundant pores for fast electrolyte access, efficient charge transfer, and strong coupling between CuCoO x and FeOOH components. Attributed to these features, the CuCoO x /FeOOH nanowires exhibit excellent bifunctional oxygen evolution reaction and oxygen reduction reaction activities, including low overpotentials, high current densities, and outstanding stabilities. Using the CuCoO x /FeOOH electrocatalyst as the oxygen electrode, a rechargeable zinc–air battery was fabricated to exhibit a small charge–discharge overpotential (0.75 V at 10 mA·cm –2 ) and a long-term cycling stability (150 cycles), thus suggesting new bifunctional electrocatalysts for energy conversion and storage applications.