Porous Copper‐PTFE Hybrid Electrocatalyst for CO₂ Reduction with High C₂₊ Selectivity

Abstract The electrochemical CO 2 reduction reaction (CO 2 RR) to ethylene (C 2 H 4 ) is one of the most promising approaches to obtaining value‐added C 2+ hydrocarbons without net CO 2 emission. However, issues still to be solved for practical use include the improvement of Faradaic efficiency (FE) towards C 2 H 4 , electrode durability, and suppression of competitive hydrogen evolution reaction (HER). In this work, hydrophobic polymer, polytetrafluoroethylene (PTFE), added porous Cu electrocatalysts were firstly and successfully prepared on gas diffusion layer, and the significant enhancement of FEs toward C 2+ products, especially C 2 H 4 , and durability were found. CO 2 RR test in flow cell as a gas diffusion electrode (GDE) revealed that the GDE with porous Cu electrocatalysts showed higher FE(C 2 H 4 ) to FE(CO) while significant HER and instability issues remained. Further modification by PTFE to form porous Cu‐PTFE hybrid structure significantly decreased FE(H 2 ) to 11.6 % in minimum, enhanced FE(C 2 H 4 ) to 51.1 % in maximum and raised durable CO 2 RR for over 24 hours under current density of −300 mA cm −2 . PTFE addition should form a secured pathway for gas species, including both reactant and product which was beneficial for durable and selective C 2 H 4 production. This work highlights chemical engineering aspects of CO 2 RR including the transportation of reactants and products.