Probing the (de)activation of Raney nickel–iron anodes during alkaline water electrolysis by accelerated deactivation testing

Abstract

We investigated the (de)activation of Raney nickel–iron anodes in various oxygen evolution reaction (OER) environments using accelerated deactivation testing (ADT) under the conditions of on/off voltage control (ADT1), constant current density (ADT2), and cyclic voltammetry (ADT3). ADT1 caused activation under OER conditions by promoting the leaching of residual zinc and thus increasing the electrode surface area and oxygen vacancy content, whereas deactivation was observed under the conditions of the hydrogen evolution reaction(H-ADT1). ADT2 decreased the OER activity by promoting NiO formation and iron leaching, while ADT3 slightly increased the OER activity by favoring the incorporation of iron into the nickel lattice and promoting nickel–iron hydroxide formation. Thus, this work facilitates the design of more efficient and durable Raney nickel–based OER anodes by providing insights into their (de)activation mechanisms.

Keywords

• Alkaline water electrolysis
• Oxygen evolution reaction
• Accelerated deactivation testing
• Raney nickel
• Electrocatalysis
• Mechanism elucidation