Causes and Effects of Unintended Cation Crossover in CO2 Reduction Cells

El-Nagar, Gumaa A. and Haun, Flora and Gupta, Siddharth and Stojkovikj, Sasho and Mayer, Matthew T. (2023) Causes and Effects of Unintended Cation Crossover in CO2 Reduction Cells. In: 244th ECS Meeting, 8 - 12 Oct 2023, Gothenburg, Sweden.

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Abstract

Electrochemically converting carbon dioxide into useful products is a promising approach to combat climate change by reducing our reliance on fossil fuels and promoting a sustainable carbon cycle. The operation of membrane electrode assemblies within gas diffusion cells facilitates the efficient reduction of CO2 at rates relevant to industrial applications. However, their long-term stability is often limited by formation of solid precipitates in the cathode pores. This is a consequence of a combination of 1) local alkalization due to the electrochemical reaction, 2) generation of (bi)carbonate by chemical reaction of CO2 with the alkaline electrolyte, and 3) the presence of alkali metal cations. In catholyte-free, zero-gap cells using anion exchange membranes, the presence of electrolyte cations at the cathode is the result of unintended crossover from the anolyte, and a detailed understanding of the factors enabling this crossover is lacking. Here we show that the anolyte concentration governs the flux of cation migration through the membrane, and this substantially influences the behaviours of copper catalysts in catholyte-free CO2 electrolyzers.
Our findings highlight the substantial impact of cation effects, including unintended crossover, even in catholyte-free cells, on reaction pathways. This aspect should be considered in the future development of catalysts and devices. As an outlook a more in-depth knowledge with the help of operando measurements could help to understand and manage cation crossover for optimizing the performance, selectivity, and durability of these electrochemical systems.

Item Type:	Conference or Workshop Item (Poster)
Subjects:	Engineering and Technology > Chemical engineering Natural sciences > Chemical sciences Natural sciences > Earth and related environmental sciences Engineering and Technology > Environmental engineering Engineering and Technology > Materials engineering Natural sciences > Physical sciences
Divisions:	Faculty of Technology
Depositing User:	Saso Stojkovik
Date Deposited:	29 Feb 2024 09:07
Last Modified:	29 Feb 2024 09:07
URI:	https://eprints.ugd.edu.mk/id/eprint/33779

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