Accelerated Durability Test for High-Surface-Area Oxyhydroxide Nickel Supported on Raney Nickel as Catalyst for the Alkaline Oxygen Evolution Reaction

Abstract

We demonstrate a fit-for-purpose accelerated durability test (ADT) of a high-surface-area catalyst for the alkaline oxygen evolution reaction (OER). Using an automatized electrochemical setup enabled us to run a complex ADT protocol including online detection of the effective solution resistance as well as linear voltammetry, cyclic voltammetry, cyclic galvanograms, and electrochemical impedance spectroscopy (EIS) for 55 h in total. Using this protocol, we tested the service life stability of a nickel oxyhydroxide (NiOx) catalyst based on Raney Ni. The catalyst was prepared by growing nickel oxyhydroxide on high-surface-area Raney Ni and subsequent formation of the active phase. The successful synthesis of the active NiOx phase is supported by cyclic voltammetry and Raman spectroscopy. The as prepared and activated Raney NiOx exhibits an overpotential for the OER of 304 mV at 10 mA cm^-2 with a Tafel slope of 53 mV dec^-1 and roughness factors as high as 4515 determined by EIS during OER. By concentrating for the ADT protocol on current densities relevant for coupling water electrolysis to photovoltaics, it is demonstrated that Raney NiOx is a promising anode material candidate as it is earth abundant and its active phase exhibits high OER activity as well as stability.

Keywords: Ni oxyhydroxide; Raney nickel; accelerated durability tests; automation; oxygen evolution reaction.