Stoma‐Shell Nanoarchitecture for Enhanced Plasma Confinement Catalysis in Synthesis of Ethanol from CO ₂

ABSTRACT Plasma catalysis realizes CO ₂ conversion under ambient conditions through the inelastic collision of high‐energy electrons, but the continuous impact of high‐energy electrons often leads to the excessive dissociation of formed intermediates. To address this limitation, we designed a biomimetic stoma‐shell nanoarchitecture, inspired by natural leaves, to enhance the selectivity of C ₂₊ products. Its microporous shell with vertically aligned pores, emulating natural leaf stomata, functions as a selective barrier that mitigates high‐energy electron impact while maintaining reactant transport. Inside, a defect‐rich mesoporous network with exposed copper sites promotes C─C coupling and stabilizes C ₂₊ intermediates within confined catalytic spaces. This functional architecture redistributes the active species within the plasma catalytic zone, thereby suppressing undesired side reactions. Catalytic results showed a significant reversal in product selectivity between methanol and ethanol, with a 3‐fold enhancement in ethanol selectivity over methanol from 24% to 65%. This work proposes an advanced functional materials design strategy that is broadly applicable to catalytic plasma‐driven reactions, integrating electron impact tolerance with catalytic efficiency to direct the desired reaction pathway.