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PRINCIPAL PUBLICATION AND AUTHORS
Identifying and alleviating the durability challenges in membrane-electrode-assembly devices for high-rate CO electrolysis, Q. Xu (a), S. Garg (a), A.B. Moss (a), M. Mirolo (b), I. Chorkendorff (a), J. Drnec (b), B. Seger (a), Nat. Catal. (2023); https:/doi.org/10.1038/s41929-023-01034-y (a) Surface Physics and Catalysis (Surf Cat) Section, Department of Physics, Technical University of Denmark, Kongens Lyngby (Denmark) (b) ESRF
REFERENCES
[1] M. Jouny et al., Nat. Catal. 2, 1062-1070 (2019). [2] Z. Wang et al., Npj Comput. Mater. 6, 160 (2020).
To summarise, synchrotron WAXS results reveal that cathodic gas diffusion electrode flooding and Ir contaminants (crossover from anode) are two major issues causing excessive HER in a short-term testing period (< 3 hours). Based on this understanding, strategic measures were implemented to alleviate these issues. These include increasing the polytetrafluoroethylene content in the gas diffusion electrodes and using an alkaline stable Ni-based anode. Consequently, a 136- hour stability with a Faradaic efficiency of CO reduction exceeding 70% relative to the hydrogen evolution reaction was achieved.
In conclusion, this work used operando WAXS to identify several degradation mechanisms of the MEA during high- rate and long-term CO electrolysis. The results provide guidelines to circumvent the durability challenges in the high-rate CO/CO2 electrolysis field, such as selecting the appropriate anode catalysts according to the reaction conditions and carefully monitoring the anodic oxidation reaction to avoid unexpected anode degradation.
Fig. 87: a) Cell voltage. b-e) the processed operando WAXS mappings by integrating corresponding fcc-structured Cu (111) peak (b), electrolyte (changes in background scattering (c), fcc-structured Ir (111) peak (d) and rutile- structured IrO2 (101) peak (e). f) Faradaic efficiencies (FE) of gas products for HER (i.e., H2) and CO reduction (including CH4 and C2H4) during CO electrolysis measurement (at 200 mA cm-2; anolyte of 0.1 M CsOH).
