Defect‐Driven Stepwise Activation of Metal–Organic Frameworks Toward Industrial‐Level Anion Exchange Membrane Water Electrolysis

Abstract

Abstract Metal‐organic frameworks (MOFs), featuring well‐defined metal active sites and unique coordination environment, have recently emerged as ideal model catalysts for establishing precise structure‐activity relationships in oxygen evolution reaction (OER). However, elucidating essential catalytic mechanisms responsible for dynamic reaction conditions remain challenging, primarily due to the complicated adsorption behavior and cross‐step transfer of key adsorbates during OER. Herein, we propose a defect‐driven stepwise activation strategy to meticulously control the adsorption behavior for defective Co‐based MOF (termed D/CoFc‐MOF) through tailoring the interplay between local coordination geometry and electronic configuration. Operando characterizations reveal that D/CoFc‐MOF undergoes a unique stepwise activation during OER, progressing from pristine MOF state to intermediate α‐FeOOH state, and ultimately to active CoFeOOH phase, which markedly differs from conventional single‐step surface phase conversion. Theoretical calculations demonstrate that the electronic interaction between the active Co sites and OOH* intermediates of MOF‐derived defective CoFeOOH can be effectively strengthened, thereby overcoming the high reaction barrier and enhancing OER activity. The D/CoFc‐MOF anode, deployed in anion exchange membrane water electrolysis, achieves industrial‐scale current densities of 1 A cm −2 at 1.69 V and operates stably for 300 h. This approach provides a fundamental insight into designing catalysts prone to dynamic phase transitions.