The Best of Both Worlds: Stacked Catalytic Layers for the Electrocatalytic Generation of CO in Zero-Gap Electrolyzers

Abstract

Tailoring the properties of the catalytic layer (CL) alongside its architecture is a key development towards ensuring both improve efficiency and selectivity for CO2 electrolyzers. Traditionally, CLs for the CO2R consist of a single binder-material or a combination of them overtaking both the ion-conductance and maintenance of a hydrophobic environment.We herein decoupled these processes into two individual, stacked catalyst-containing layers. Specifically, a hydrophobic catalytic layer was herein placed on the GDL aiming to improve water management within the CL during CO2R in zero-gap electrolyzers, while A second catalytic layer bound by an ion-conducting binder allows for the conduction of OH- and HCO3-/CO3 2- during CO2R, improving both the ionic conductivity between the GDE and AEM as well as the mechanical adhesion between the different interfaces. Notably, we present the complete stepwise CL-optimization pathway, regarding both the single and segmented-CLs towards the CO2-CO conversion at current densities ≥ 300 mA cm2, highlighting the role of the operational parameters regarding scalability in different cell sizes and long-term stability > 100 h.