A comparative study on the oxygen evolution reaction of cobalt and nickel based hydroxide electrodes in alkaline electrolyte

Abstract

• Co and Ni-based hydroxide nanostructures are prepared by electrodeposition. • Systematic comparison of five discrete electrocatalysts for OER. • Co(OH) 2 @Ni shows a favorable performance on water oxidation with better durability. Oxygen evolution reaction (OER) plays the key role in determining the kinetics of the electrochemical water splitting reaction. The natural abundancy and unique redox properties of transition metal-based (oxy)hydroxides with layered structure make them one of the most preferred OER electrocatalysts in alkaline medium. Herein, we fabricated a set of Co– and Ni-based hydroxide nanoflakes/nanowalls on conductive Ni foam substrate via a simple and quick electrochemical deposition method. OER experiments were systematically conducted on Co(OH) 2 @Ni, Ni(OH) 2 @Ni, NiCo LDH@Ni, Co(OH) 2 /Ni(OH) 2 @Ni, Ni(OH) 2 /Co(OH) 2 @Ni electrocatalysts. The results from the OER experiments reveal that Co(OH) 2 @Ni nanostructures are the best electrocatalyst with the lowest overpotential and have preserved their morphology after 24 h of chronopotentiometric test. It is believed that the current work will provide an idea of how Co– and Ni-based hydroxide or their combination can influence OER.