Deciphering the Exceptional Performance of NiFe Hydroxide for the Oxygen Evolution Reaction in an Anion Exchange Membrane Electrolyzer

Abstract

Hydrogen production via water electrolysis with renewable electricity as input will be crucial for the coming defossilized energy age. Herein, we report an anion exchange membrane electrolyzer using Fe-doped Ni hydroxide as an anode catalyst that is on par with proton exchange membrane electrolyzers in terms of the performance, 2 A cm-2 at 2.046 V and 50 °C. We found that Fe doping stabilizes the α-Ni(OH)2 phase, which is key to ensure the fast Ni(OH)2/NiOOH redox transition and the subsequent fast reaction between Ni3+/4+ and the electrolyte (OH-), resulting in the excellent oxygen evolution reaction activity of Fe-doped Ni hydroxide. Spin-polarized DFT + U computations reveal that the local arrangement of Fe3+ with Ni3+/4+ plays a crucial role in enabling the high OER activity on the (001) facet of this anode catalyst.