Rational catalyst layer design enables tailored transport channels for efficient CO2 electrochemical reduction to multi-carbon products†

Abstract

Membrane electrode assemblies (MEAs) have been developed for electrochemical conversion of CO₂ to high-value multi-carbon (C₂₊) products at industrial current densities (j > 200 mA cm⁻²). However, the effective and simultaneous modulation of CO₂ and H₂O mass transfer within MEA remains a critical issue, particularly at the three-phase interface. Herein, CO₂ and H₂O channels are incorporated into the catalyst layer network to benefit the micro-environment. The balance of local CO₂ and H₂O at the reaction interface is attained by regulating the catalyst-coated ionomer. In situ DEMS further confirms that the rational routes are successfully established for mass transfer management. The interfacial distribution of CO₂ and H₂O is in-depth investigated via in situ ATR-SEIRAS and molecular dynamics (MD) simulation. Through reasonable catalyst layer design, CO₂-to-C₂₊ performance is substantially enhanced, exhibiting remarkable selectivity to C₂₊ products with a faradaic efficiency (FE) of 89.4 ± 0.69% and a partial current density of 536 ± 4.14 mA cm⁻². The optimized Cu-GDE also exhibits excellent stability of >10 h at a total current of 2 A.