From binary to ternary: NiFeM alloys in unified electrodes for high performance anion-exchange membrane water electrolysis

Abstract

The advancement of highly active oxygen evolution reaction (OER) at the anode of anion-exchange membrane water electrolysis (AEMWE) is essential for the commercialization of green hydrogen. In this study, we present a unified electrode that combines nickel–iron-based ternary alloys with various transition metals. The investigation focused on the types and compositions of the ternary alloys to create a unified electrode demonstrating the highest OER activity. Furthermore, the impact of the ternary alloy on the unified electrode was examined. The unified electrode incorporating the NiFeCo ternary alloy (UE-NiFeCo) displayed the highest OER activity and maintained stability over 1000 h. The AEMWE performance at 1.9 V using UE-NiFeCo reached 5,311 mA cm⁻², surpassing other variants (Cu and La). Notably, UE-NiFeCo outperformed the unified electrode utilizing the NiFe binary alloy, suggesting that the inclusion of Co atoms in NiFe enhanced the OER activity, consequently improving AEMWE performance. Furthermore, UE-NiFeCo exhibited superior performance compared to a commercial electrode prepared via the spraying method, as the unified electrode enhanced activation, ohmic, and mass transport processes in the AEMWE.