Crystallinity modification of NiFe layered double hydroxide for efficient and durable oxygen evolution in alkaline water electrolysis

Abstract

NiFe-layered double hydroxide (NiFe-LDH) is recognized as an efficient electrocatalyst for the oxygen evolution reaction (OER), but its performance is limited compared to noble metal catalysts due to high resistance from OH− transport through its 2D layered structure. Herein, we propose reducing this resistance by decreasing the crystallinity of NiFe-LDH via in-situ electrochemical modification using cyclic voltammetry (CV) commonly used for activating catalysts in half-cell investigation. After modification (NiFe-LDH_WideCV), the crystal size of the 2D structure is reduced by 23% compared to the catalyst activated by the conventional process (NiFe-LDH_ShortCV), improving the kinetics of OH− redox reaction. As a result, NiFe-LDH_WideCV requires 12 mV less overpotential for alkaline OER at 10 mA cm−2. Furthermore, after 120 h of durability testing, NiFe-LDH_WideCV exhibits 30.7% less Fe leaching than NiFe-LDH_ShortCV with improving durability by 47%. This study introduces an effective method for enhancing NiFe-LDH catalysts, making them more suitable for practical water electrolysis applications. © 2026 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.