Outstanding oxygen evolution reaction performance of nickel iron selenide/stainless steel mat for water electrolysis

Stainless steel (SS) has been widely incorporated into electrodes or used as a conductive scaffold in industrial water electrolysis. Operations using such SS-bearing materials proceed under substantial overpotentials above the thermodynamic requirement due to the sluggish kinetics of the anodic oxygen evolution reaction (OER). Traditional surface engineering of SS involves a corrosion process to optimize its composition and modify its surface morphology, but its catalytic properties remain unsatisfactory even after employing this technique. Here, we introduce an effective route, based on surface decoration, to construct a ternary phase composed of nickel iron selenide (NiFeSe) uniformly distributed on a stainless-steel mat (SSM). NiFeSe/SSM was found to require an overpotential of only 260 mV to drive a current density of 1,000 mA cm(-2) at 75 degrees C in alkaline solution, one of the best results among SS-based and even transition metal-based catalysts for OER. Additionally, this NiFeSe/SSM electrode shows negligible potential degradation after operating at 1,000 mA cm(-2) for 55 h. It is suggested that Se in the nickel iron selenide directly binds to the SSM through strong covalent bonding during selenization, which guarantees low charge-transfer resistance and excellent durability against the gas bubbles produced during operation at large current densities. This work opens a new route for performing surface engineering on SS or other conductive substrates to achieve superior OER performance. (C) 2020 Elsevier Ltd. All rights reserved.