Mn^I‐Functionalized Covalent Organic Framework as Efficient Electrocatalyst for CO₂ Reduction in a Catholyte‐Free Zero‐Gap Electrolyzer

Abstract Covalent Organic Frameworks (COFs) have emerged as versatile platforms for the rational design of heterogeneous CO 2 electrocatalysts, offering molecular‐level precision due to their well‐ordered, porous structures. While COF‐based hybrid electrocatalysts have demonstrated potential in lab‐scale electrochemical cells with liquid electrolytes, their application in industry‐relevant architectures remains largely unexplored. Here, the first successful integration of a phenanthroline‐based 2D COF, modified with Mn I single catalytic sites, into a catholyte‐free membrane‐electrode‐assembly (MEA) cell for CO 2 electroreduction is presented. The crystalline COF catalyst achieves an outstanding turnover frequency of 617 h⁻ 1 (quantified per total concentration of catalytic sites) and a CO evolution of 222 µmol cm⁻ 2 (at a full‐cell potential of 2.8 V) within 30 min. Moreover, the COF structure actively suppresses Mn⁰–Mn⁰ dimer formation and supports stable operation at high potentials with a partial current density of 23 mA cm −2 . The synergy between the crystalline nature of the COF and the MEA cell architecture, facilitating direct interactions between the modified electrode and the CO 2 gas, enhances both the catalytic activity and stability. This work paves the way for broader adoption of COF‐based hybrid materials in advanced electrocatalytic CO 2 reduction technologies.