Vertically oriented CoO@FeOOH nanowire arrays anchored on carbon cloth as a highly efficient electrode for oxygen evolution reaction

Developing high efficiency electrocatalysts for electrocatalytic oxygen evolution reaction (OER) is a key to water splitting. In this work, we demonstrate the preparation of CoO@FeOOH core-shell nanowire (NWs) grown on three-dimensional (3D) carbon cloth (CC@CoO@FeOOH-NWAs) by hydrothermal method followed by electrodeposition process as well as its highly efficient activity for water oxidation. In this hybrid structure, CoO@FeOOH-NWs with an average diameter of 100 nm is vertically grown on the surface of carbon fibers of the carbon cloth. The combination of CoO@FeOOH catalyst with good electron transfer substrate exhibits exceptionally good electrocatalytic activity and long-term durability towards oxygen evolution reaction in alkaline solution. It needs an overpotential as low as 255 mV to achieve the current density of 10 mA cm⁻², with a Tafel slope of 82 mV dec⁻¹ and also exhibits a good stability in 20 h. In addition, the nanowire array structure is well retained after the durability test with high current density of 50 mA cm⁻². Our strategy provides a guide to rational design of micro-structures of the materials to achieve their high performance.