Development of Ternary Layered Double Hydroxide Oxygen Evolution Reaction Electrocatalyst for Anion Exchange Membrane Water Electrolysis

Abstract

To achieve net zero emissions, green hydrogen should be produced via water electrolysis with renewable energy. To develop efficient anion exchange membrane water electrolyzers (AEMWE), the development of efficient and stable non-precious metal electrocatalysts for the oxygen evolution reaction (OER) is essential. In this study, a high-performance ternary NiFeCo-layer double hydroxide (LDH) electrocatalyst for AEMWE was easily developed by the co-precipitation method. The introduction of Co has been shown to have an effect on the electronic structure of Ni and Fe, improving their intrinsic OER properties. In addition, the three-dimensional flower-like nanosheet morphology improved mass transfer and achieved excellent current density at high voltages. The ternary NiFeCo-LDH electrocatalyst requires low overpotentials (253 mV at 10 mA cm<sup>-2</sup>) and Tafel slope (45 mV dec<sup>-1</sup>) in 1 M KOH. AEMWE using the ternary NiFeCo-LDH electrocatalyst showed excellent electrolysis performance with a high current density of 2.27 A cm<sup>-2</sup> at 1.8 V cell. Moreover, an energy conversion efficiency of 86.73 % was achieved during the durability test for 100 hours at a current density of 0.5 A cm<sup>-2</sup>. The performance of the AEMWE electrolyzer utilizing the ternary NiFeCo-LDH electrocatalyst surpassed that of previously reported AEMWE electrolyzers. This work reports a highly active OER electrocatalyst that could open numerous opportunities for the development of ternary LDH electrocatalysts in AEMWE.