(390e) Novel Structure of Gas Diffusion Electrode for Electrocatalytic Reactions: Conductive Polymer-Coated Hydrophobic Membrane

As the threat of global warming becomes more severe, the necessity for the development and commercialization of CO₂ conversion technologies has arisen. Electrochemical CO₂ reduction reaction (CO2RR) is a promising approach for upcycling CO₂, since net zero, even negative emission of CO₂ can be achieved by combining with renewable electricity sources. In order to operate electrolyzers in industrial-scale current regimes, the application of gas diffusion electrodes (GDEs) in flow cell configurations is essential to enhance CO₂ accessibility. However, existing GDE systems suffer from electrolyte flooding, which blocks CO₂ transport, limits CO2RR, and triggers unwanted reactions, resulting in a decrease in catalytic performance. Some studies exhibited the usage of polytetrafluoroethylene (PTFE) as GDE with enhanced stability, but fabrications were limited to the sputtering of metal electrocatalysts on PTFE requiring special equipment. Herein, we conceived a new structure of PTFE-based GDE, which has a porous and electrically conductive polymer layer on top of the PTFE side to maintain the properties of PTFE while enabling .

Poly(3,4-ethylenedioxythiophene) (PEDOT) was used as a conductive polymer and was electrochemically synthesized on the PTFE membrane. A thin layer with a thickness of 1 μm was formed and its porous structure was identified by microscopic analysis. The efficacy of this GDE structure was demonstrated during CO2RR. Ag nanopowders were loaded on PEDOT/PTFE and operated at industrially relevant current density under acidic, neutral, and alkaline electrolytes. The results indicate that PEDOT/PTFE achieved comparable results as a cell with a carbon-based GDE in terms of faradaic efficiency and applied potential. Furthermore, the performance from PEDOT/PTFE showed enhanced stability compared to the carbon-based GDE, which showed significant activity decreases after several hours of operation. This work demonstrates that polymer-coated PTFE GDE is a promising alternative to conventional carbon-based GDE, allowing GDE to be stable for extended operation without electrolyte flooding.