CuCoOx/FeOOH Core-Shell Nanowires as an Efficient Bifunctional Oxygen Evolution and Reduction Catalyst

Abstract

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 (CuCoOx/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 CuCoOx and FeOOH components. Attributed to these features, the CuCoOx/FeOOH nanowires exhibit excellent bifunctional oxygen evolution reaction and oxygen reduction reaction activities, including low overpotentials, high current densities, and outstanding stabilities. Using the CuCoOx/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.