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 CO 2 ‐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 (FE CO ) 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 FE CO of 80 %.