Topologically Programmed Dual-Channel Covalent Organic Frameworks Decouple Gas and Ion Fluxes for Acidic CO2 Electroreduction.

High-rate CO2 electroreduction in acid is severely restricted by the intrinsic trade-off between gas and ion transport. In conventional catalyst layers, these conflicting transport requirements are spatially entangled within the same disordered pore network, leading to severe mass transport limitations and salt precipitation at industrial current densities. Here, we report a dual-channel covalent organic framework (COF) binder designed to structurally decouple gas and ion fluxes. The Kagome-topology framework features hydrophobic CF3-lined triangular channels for unimpeded CO2 diffusion and separate hexagonal channels functionalized with ionic groups for electrolyte transport. We find that the cationic derivative (C-iCOF) effectively exports locally generated OH-, thereby buffering the interfacial pH and mitigating carbonate formation. At 300 mA cm-2 in acidic media (pH = 1), the Cu/C-iCOF catalyst achieves a 49.1% ethylene Faradaic efficiency (FE) and a 42.7% single-pass carbon efficiency (SPCE) for C2+ products. Mechanistic studies reveal that the cationic channels stabilize an ordered interfacial water network and *CO intermediates, favoring C-C coupling through an Eley-Rideal (ER) pathway while suppressing hydrogen evolution. These findings demonstrate that the topological separation of transport pathways is effective for managing the microenvironment in gas-involving multiphase electrocatalysis.