Operando Multi-Modal Liquid-Electrochemical Electron and X-Ray Microscopy of CO2 Electrocatalysis

• Published in: Meeting abstracts (Electrochemical Society) Vol. MA2025-01; no. 50; p. 2509
• Main Authors: Parkin, Calvin, Kim, Juwon, Lim, Jongwoo, Grosse, Philipp, Avila-Bolivar, Beatriz, Chee, See Wee, Alsem, Daan Hein
• Format: Journal Article
• Language: English
• Published: The Electrochemical Society, Inc 11.07.2025
• ISSN: 2151-2043; 2151-2035
• DOI: 10.1149/MA2025-01502509mtgabs

Operando liquid cells compatible with transmission electron, scanning electron and scanning transmission x-ray microscopy (TEM, SEM, and STXM) have enabled dynamic studies of structural and chemical changes to electrocatalysts under electrochemical CO2 reduction conditions and revealed mechanistic connections to their performance. Such fundamental structure-property relationships are critical to improving the performance of nanocatalysts in industrial processes. Growing research interest in nanoscale electrocatalysts has accelerated the development of in-situ liquid-electrochemical microscopy techniques into robust characterization workflows spanning multiple characterization techniques and scales. Multiple characterization techniques are often required to fully understand the mechanisms governing the behavior of electrocatalysts for all relevant length scales and environmental conditions. New scientific hardware and method development has been critical to in-situ nano-scale liquid cell microscopy and spectroscopy of electrochemical systems. In particular, incorporation of bulk-scale reference and counter electrodes has yielded quantitatively higher fidelity electrochemical data with reduced electrode degradation over extended cycling of the cell. Such techniques are applied to characterization of electrocatalysis processes under TEM, SEM, and STXM to demonstrate the variety of experiments enabled. Optimization of Cu catalyst selectivity via electrodeposition synthesis processes are observed in-situ under SEM. Restructuring of Bi2O3 into Bi nanosheets in the presence of KHCO3 and subsequent dissolution with sustained negative applied potential is observed in TEM. Finally, cationic Cu species are tracked using operando STXM, with phase changes and morphological evolution linked to selectivity for C-C coupling. New insights into these materials systems provided by these experiments will directly inform the development of predictive models for electrocatalyst performance and guide improvement of catalyst particle design, synthesis, and utilization. Additional capabilities enabling operando characterization of photoelectrochemical and high temperature systems are also discussed.