Hoof, LucasLucasHoofPellumbi, KevinjeorjiosKevinjeorjiosPellumbiGüney, Didem CansuDidem CansuGüneyBlaudszun, DennisDennisBlaudszunBommas, FranzFranzBommasSiegmund, DanielDanielSiegmundjunge Puring, KaiKaijunge PuringCao, RuiRuiCaoWeber, KatharinaKatharinaWeberApfel, Ulf-PeterUlf-PeterApfel2025-03-182025-03-182025https://publica.fraunhofer.de/handle/publica/48562110.1039/d4su00453aTailoring the properties of the catalytic layer (CL) and its architecture is crucial for enhancing both the efficiency and selectivity of CO2 electrolysers. Traditionally, CLs for CO2 reduction comprise of a single binder material or a combination that handles both ion conductance and the maintenance of a hydrophobic environment. In this work, we decouple these processes into two individual, stacked catalyst-containing layers. Specifically, a hydrophobic catalytic layer is placed on the gas diffusion layer to improve water management within the CL during CO2R in zero-gap electrolysers. Additionally, a second catalytic layer, bound by an ion-conducting binder, facilitates the conduction of OH- and HCO3-/CO32- during CO2R, thereby enhancing both ionic conductivity between the GDE and anion exchange membrane (AEM), as well as mechanical adhesion between different interfaces. Notably, we present a comprehensive stepwise optimization pathway for the CL, addressing both single and stacked CLs for CO2-to-CO conversion at current densities of 300 mA cm-2.encatalytic layer (CL)CO2 electrolysiszero-gap electrolysissustainability, environmentaljournal article