Thin-Layered Cobalt-Based Catalysts on Stainless-Steel Microfibers for the Efficient Electrolysis of Water

Abstract

Herein, we introduce a highly catalytic core-shell microfiber electrode based on a cobalt oxygen-evolving catalyst (Co-OEC) electrodeposited on a three-dimensional (3D) mat of stainless-steel (SS) microfibers. The resulting core-shell microfibers (Co-MF) with a catalytic shell exhibit a turnover frequency and a current density that are much higher than those of a conventional Co-OEC on a flat SS foil (Co-F) at neutral pH. The onset potential of the catalytic wave of Co-MF is also appreciably lower than that of Co-F owing to a combination of the higher surface activity of the Co-OEC and the enhanced local electric field in the 3D network of the metal microfibers. This study suggests that cost-effective, stable, and earth-abundant SS microfibers can be a promising substrate to enhance the surface activity of water-oxidation electrocatalysts.