Electrocatalytic Functionalized Specialty Paper as Low-Cost Porous Transport Layer Material in CO₂-Electrolysis

The development of low-cost and efficient electrolyzer components is crucial for practical electrochemical carbon dioxide reduction (ECR). In this study, facile non-woven cellulose-based porous transport layers (PTLs) were developed for high current density CO2-to-CO conversion. By depositing a cobalt phthalocyanine (CoPc) catalyst-layer over the PTLs, we fabricated ECR-functioning gas-diffusion-electrodes (GDEs) for both flow-cell and zero-gap electrolyzers. Under optimal conditions, the Faradaic efficiency of CO (FECO) reached 92 % at a high current density of 200 mA cm(-2). Furthering the architecture of the GDEs, CoPc was incorporated into the initial PTL slurry, forming ECR-active PTLs without the need for an additional catalyst-layer. The new GDE-architecture favored the CoPc-distribution by enhancing the contact and interactions with the carbon substrate and demonstrated a stable electrolysis process for over 50 h in a zero-gap cell at 200 mA cm(-2) with a FECO of 80 %.