Regulating water transport and salt precipitation for CO2RR by creating a functional layer

The zero-gap reactor design for CO2 electrochemical reduction employs gas diffusion electrodes (GDEs) to shorten mass transport distances. Despite its advantages, it faces challenges like ensuring sufficient water supply to the cathode while preventing flooding and salt precipitation. In this study, we present a novel electrode design that incorporates a functional layer coated on the catalyst layer to regulate water transport and inhibit salt precipitation. This design reduces the water crossing the membrane and alleviates salt precipitation, achieving a CO partial current density of up to 303 mA/cm2 at 2.6 V, with a Faradaic efficiency for CO exceeding 99%. Our findings offer crucial insights into improving GDEs for zero-gap electrolyzers and address the issues of salt precipitation and flooding.