Along with mitigation, the effective utilization of waste CO and CO₂ from point sources in combination with renewable electrons has the potential to address climate challenges and change the manufacturing paradigm. Numerous funding offices and governments have set device level goals and reduction targets for CO₂ emissions putting momentum behind and a focus on electrochemical CO/CO₂ reduction. To enable this vision, the identification of limiting phenomena,[1,2] scalable integration and fabrication methods, and corresponding critical breakthroughs to improve stability (constant operation) and/or durability (dynamic operation), combined with selective as well as efficient operation are necessary.

The implementation of gas diffusion electrodes over the last several years has enabled higher current densities and lower cell voltages for electrochemical CO/CO₂ reduction.[3,4] Here, we pull from our experience in the fuel cell space and aim to serve as a node for the development of cell and electrode architectures that would help the community integrate novel materials (electrocatalysts, membranes, and ionomers), test devices at scales commensurate with the standards in the fuel cell and electrolysis community (>25 cm²), and subsequently characterize and model limiting phenomena. To this end, we will present limiting phenomena for CO₂ to formate, CO₂ to CO, and CO to various products, focusing on the effects of cathode composition, ionomer binder chemistry and content, electrode fabrication processes, device configuration, and reactant concentrations.

[1] R. Kas, A.G. Star, K. Yang, T. Van Cleve, K.C. Neyerlin, W.A. Smith, Along the Channel Gradients Impact on the Spatioactivity of Gas Diffusion Electrodes at High Conversions during CO ₂ Electroreduction, ACS Sustainable Chemistry & Engineering. 9 (2021) 1286–1296. https://doi.org/10.1021/acssuschemeng.0c07694.

[2] S. Verma, X. Lu, S. Ma, R. I. Masel, P.J. A. Kenis, The effect of electrolyte composition on the electroreduction of CO 2 to CO on Ag based gas diffusion electrodes, Physical Chemistry Chemical Physics. 18 (2016) 7075–7084. https://doi.org/10.1039/C5CP05665A.

[3] Y. Chen, A. Vise, W.E. Klein, F.C. Cetinbas, D.J. Myers, W.A. Smith, T.G. Deutsch, K.C. Neyerlin, A Robust, Scalable Platform for the Electrochemical Conversion of CO ₂ to Formate: Identifying Pathways to Higher Energy Efficiencies, ACS Energy Letters. 5 (2020) 1825–1833. https://doi.org/10.1021/acsenergylett.0c00860.

[4] D. Higgins, C. Hahn, C. Xiang, T.F. Jaramillo, A.Z. Weber, Gas-Diffusion Electrodes for Carbon Dioxide Reduction: A New Paradigm, ACS Energy Letters. 4 (2019) 317–324. https://doi.org/10.1021/acsenergylett.8b02035.