Optimizing Electrochemical Interfaces and Device Architectures for Electrochemical Cox Reduction
Authors: Neyerlin Kenneth C. 
Published: December 2024

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] scalable integration and fabrication methods, and corresponding critical breakthroughs to improve stability (constant operation) and/or durability (dynamic operation), combined with selective and energy 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.[2,3] Here, we pull from our experience in the fuel cell space,[4] aiming 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) and test devices at scales commensurate with the standards in the fuel cell and electrolysis community (>25 cm2). 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[5] and content, electrode fabrication processes[6], device configuration[7], and reactant concentrations.
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[2] 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.
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[4] T. Van Cleve, G. Wang, M. Mooney, C.F. Cetinbas, N. Kariuki, J. Park, A. Farghaly, D. Myers, K.C. Neyerlin, Tailoring electrode microstructure via ink content to enable improved rated power performance for platinum cobalt/high surface area carbon based polymer electrolyte fuel cells, Journal of Power Sources 482 (2021) 228889. https://doi.org/10.1016/j.jpowsour.2020.228889.
[5] Y. Chen, J.A. Wrubel, A.E. Vise, F. Intia, S. Harshberger, E. Klein, W.A. Smith, Z. Ma, T.G. Deutsch, K.C. Neyerlin, The effect of catholyte and catalyst layer binders on CO2 electroreduction selectivity, Chem Catalysis 2 (2022) 400–421.
[6] D. Henckel, P. Saha, F. Intia, A.K. Taylor, C. Baez-Cotto, L. Hu, M. Schellekens, H. Simonson, E.M. Miller, S. Verma, S. Mauger, W.A. Smith, K.C. Neyerlin, Elucidation of Critical Catalyst Layer Phenomena toward High Production Rates for the Electrochemical Conversion of CO to Ethylene, ACS Appl. Mater. Interfaces 16 (2024) 3243–3252. https://doi.org/10.1021/acsami.3c11743.
[7] L. Hu, J.A. Wrubel, C.M. Baez-Cotto, F. Intia, J.H. Park, A.J. Kropf, N. Kariuki, Z. Huang, A. Farghaly, L. Amichi, P. Saha, L. Tao, D.A. Cullen, D.J. Myers, M.S. Ferrandon, K.C. Neyerlin, A scalable membrane electrode assembly architecture for efficient electrochemical conversion of CO2 to formic acid, Nat Commun 14 (2023) 7605. https://doi.org/10.1038/s41467-023-43409-6.