Phase Equilibrium Regulation in ZIF-67-Derived Electrocatalysts: Degradation Mechanism and Stability Enhancement for Oxygen Evolution Reaction

作者：Cheng Han, Yao Lv, Xuan Tang, Sixie Zhang, Yongjun Jiang, Zhiyi Lu, Sheng Dai · 发表于：Nano Letters · 年份：2025 · DOI：10.1021/acs.nanolett.5c02869 · 被引用次数：25 · 研究领域：Electrocatalysts for Energy Conversion、Fuel Cells and Related Materials、Electrochemical Analysis and Applications

Metal–organic frameworks (MOFs) like ZIF-67 are promising electrocatalysts due to their tunable structures and porosity, but their instability in aqueous electrolytes requires a deeper understanding. This study investigates the structural evolution and degradation mechanism of ZIF-67 during the oxygen evolution reaction (OER) in alkaline media. Using atomic-resolution identical-location transmission electron microscopy, we reveal its transformation pathway: ZIF-67 first converts to Co(OH) 2, then progressively evolves into catalytically active CoOOH and inactive CoO species, ultimately establishing a dynamic three-phase equilibrium under operational conditions. Prolonged cycling drives the irreversible conversion of Co(OH) 2 to CoO, depleting the Co(OH) 2 reservoir required to sustain the active CoOOH phase via equilibrium dynamics. By lowering the reaction temperature (e.g., to 0 °C), Co(OH) 2 preservation improves stability, reducing overpotential increases after 5000 cycles to just 9 mV (10 mA cm –2 ) and 15 mV (100 mA cm –2 ), outperforming room-temperature performance. These insights highlight phase equilibrium regulation as a key strategy for enhancing the MOF-derived catalyst durability.