<scp>CO₂</scp> electroreduction in a bubble‐plate electrolyzer: A new route to scale up

Abstract CO 2 electroreduction (CO 2 ER) provides a promising pathway for carbon utilization, but achieving high single‐pass conversion is hindered by mass transfer limitations and the scalability constraints of conventional reactor designs. This work introduces a novel bubble‐plate electrolyzer (BPE) that incorporates cobalt phthalocyanine (CoPc) catalysts immobilized on carbon paper substrates. This design creates abundant dynamic triple‐phase interfaces, enhancing mass transfer and reaction kinetics. A gas‐facing catalyst configuration optimizes bubble‐catalyst interactions, resulting in exceptional catalytic performance and enabling scalable reactor design. A multi‐layer BPE architecture achieves a remarkable single‐pass CO 2 conversion of 28.74%, a substantial increase from the single‐layer 6.11%, while maintaining excellent kinetic similarity and operational simplicity. Mechanistic studies reveal that a synergistic interplay between current density and CO 2 concentration governs CO 2 reduction within the BPE, where the unique gas flow configuration optimizes reactant residence time. This innovative BPE design provides a compelling strategy for practical and scalable carbon conversion technologies.