Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 96: Solid-Liquid Interfaces IV: Reactions and Electrochemistry
O 96.2: Vortrag
Donnerstag, 21. März 2024, 15:15–15:30, TC 006
Multiscale modeling reveals mass transport-controlled product selectivity in electrochemical CO2 reduction on Cu — •Adith Ramakrishnan Velmurugan1, Youngran Jung2, Dae-Hyun Nam3, and Stefan Ringe1 — 1Korea University, Seoul, Republic of Korea — 2Seoul National University, Seoul, Republic of Korea — 3DGIST, Daegu, Republic of Korea
Electrochemical CO2 reduction, one of the most promising processes for a sustainable closure of the artificial carbon cycle, is severely limited by the lack of a catalyst that can reduce CO2 to higher-reduced chemicals actively and selectively. Cu is the only catalyst found to produce considerable amounts of C2 products, albeit at high overpotentials. The conversion mechanism is unclear, with different active sites and rate-determining steps being proposed. In addition, the mass transport of CO2 has been suggested to significantly impact the product selectivity. Gas-diffusion-layer (GDL)-based electrolyzers have become a state-of-the-art solution to circumvent these mass transport limitations. In this work, we present a new multi-scale model based on first-principles kinetics, and a modification of a recently reported gas diffusion electrode model. From this model, we show that even in GDL systems, mass transport is the limiting factor governing all experimentally observed trends in product selectivity, irrespective of the reaction mechanism or product pathway. We further find indications of C2/C1 product selectivity being dependent on the pore size and depth. This work provides strong evidence for the importance of mass transport in designing CO2 electrolyzers.
Keywords: Electrochemical CO2 reduction; Copper; Gas diffusion electrodes; Multiscale modeling; Mass transport