Nanowire-Based Composite Electrodes for Ampere-Level Electrochemical Reduction of CO2 to Multi-Carbon Productsvia Accelerated Mass Transport

Achieving ampere-level CO2 electroreduction to multicarbon (C2+) products requires resolving the system-level mass-transport bottleneck inherent to conventional carbon-based gas-diffusion electrodes (GDEs)—namely, a sub-100 nm microporous layer (MPL) and electrowetting-induced flooding under alkaline, high-current-density conditions. Guided by mass-transport simulation, we design a composite GDE comprising a Nafion-coated Cu nanowire (NW) network catalyst layer (CL) and a hydrophobic, MPL-free polytetrafluoroethylene (PTFE) gas-diffusion layer (GDL). The macroporous Cu NW network is intrinsically conductive and enables independent optimization of GDL pore size and CL thickness within a coupled mass-transport architecture. The optimized configuration delivers a Faradaic efficiency of 88.1% and a partial current density of –1.19 A cm–2 for C2+ products while still retaining 71.9% C2+ selectivity with a dilute CO2 feed (15%). Advanced operando spectroscopy characterization reveals that accelerated CO2 flux elevates *CO surface coverage, lowering the C–C coupling onset by ∼60 mV. This work offers important insights into the role of mass transport in industry-relevant CO2-to-C2+ conversion.