Mechanically stabilized porous aerophilicity unlocks ampere-rate transport-limited CO2 electroreduction to ethylene

Gas-fed electrochemical CO 2 reduction (CO 2 R) to multicarbon products is fundamentally constrained by mass-transport limitations that suppress selectivity and stability at industrially relevant current densities. Here, we demonstrate that these bottlenecks can be overcome by engineering a porous aerophilic polymer microenvironment around a simple Cu x O electrocatalyst without altering the intrinsic catalyst. By systematically replacing conventional PFSA ionomers with mixed aerophilic binders and applying a mild thermal treatment, we construct mechanically stabilized, gas-accessible overlayers that regulate the local gas-liquid microenvironment balance at the three-phase boundary (TPB). This approach drives a dramatic enhancement in ethylene production, increasing the partial current density from 135 mA cm −2 at 27 ± 5% Faradaic efficiency for Cu x O with PFSA ionomer to over 650 mA cm −2 at 65 ± 4% Faradaic efficiency upon incorporation of a porous and aerophilic FEP/PTFE overlayer. Comprehensive microscopy and spectroscopy reveal intimate polymer-catalyst integration and overlayer consolidation, while COMSOL multiphysics modeling links enhanced CO 2 availability to mitigated flooding rather than intrinsic kinetic acceleration. These results establish transport engineering as a powerful, catalyst-agnostic lever for advancing gas-phase electrosynthesis under high-rate operating conditions.