Synthesis of Co <sub>3</sub> O <sub>4</sub> ‐Fe <sub>2</sub> O <sub>3</sub> via high‐energy ball milling for efficient oxygen evolution reaction in water splitting
Sungjun Heo, Chiho Kim, Jooyoung Lee, Song Jin, Jae‐Yeop Jeong, Shin‐Woo Myeong, Hoseok Lee, Eon‐ju Park, Minjeong Park, Sung Mook Choi
Abstract
Abstract This research explores the high‐energy ball milling (BM) method to synthesize Co 3 O 4 ‐Fe 2 O 3 electrocatalysts with enhanced oxygen evolution reaction (OER) properties. The BM process offers several critical advantages, including significantly improved catalyst uniformity, enhanced interfacial contact between Co 3 O 4 and Fe 2 O 3 , reduced particle size, and optimized surface chemical states. These modifications collectively contributed to superior OER kinetics and mass transfer, addressing key limitations in conventional electrocatalysts. The BM‐3h‐treated Co 3 O 4 ‐Fe 2 O 3 achieved a low overpotential (306.9 mV at 50 mA/cm 2 ) and a high current density (411.4 mA/cm 2 at 1.7 V vs. RHE). These results underscore the synergistic effects of enhanced structural and chemical properties achieved through the BM process. Furthermore, the practicality of the BM–Co 3 O 4 ‐Fe 2 O 3 catalyst was validated by its successful application as an anode in anion exchange membrane water electrolyzer (AEMWE) cells. The AEMWE cell demonstrated stable operation under harsh conditions, highlighting the catalyst's durability and efficiency. These results highlight the potential of the BM method as an efficient strategy for developing durable and high‐efficiency electrocatalysts for water‐splitting applications.