Visualizing degradation mechanisms in a gas-fed CO₂ reduction cell via operando X-ray tomography
Creators
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1.
California Institute of Technology
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2.
Lawrence Berkeley National Laboratory
Abstract
We utilize operando X-ray computed tomography, coupled with real-time electrochemical analysis, to reveal the underlying failure mechanisms of membrane electrode assemblies (MEAs) for electrochemical CO2 reduction (eCO2R). Through operando imaging, we can obtain unprecedented insights into the dynamic behavior of the MEA under different operating conditions, revealing critical changes in interface interactions, phase distribution, and structural integrity over time. Our findings identify phenomena giving rise to the transition from CO2R to the hydrogen evolution reaction (HER), as evidenced by shifts in cathode potential and CO2R selectivity. The formation of inhomogeneous precipitates at the gas diffusion electrode disrupts the CO2 supply and reduces the active sites for eCO2R, resulting in a shift toward H2 production during low current density operation. Additionally, under high current density conditions, rapid water crossover up to the microporous layer/gas diffusion layer promotes the transition from CO2R to HER, further shifting cell potential toward anodic direction. Oscillating voltage conditions reveal the dissolution and regrowth of precipitates, providing direct visualization of the competing selectivity of CO2R and HER. This work offers new insight into the degradation mechanisms of MEAs, with implications for the design of more durable CO2R systems.
Acknowledgement
This work was performed by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub, under Grant DE-SC0021266. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231.
Copyright and License
© 2025 The Author(s).
Supplemental Material
Data Availability
The data supporting this article have been inlcuded as part of the SI.
Supplementary information is available. See DOI: https://doi.org/10.1039/d5ey00232j
Contributions
S. A. L. wrote the manuscript with the assistance of W. D., H. A. A., and C. X. I. S. and M. J. J. contributed to the design of the electrochemical cell for X-ray tomography imaging. S. A. L., M. J. J., and Z. Q. performed the electrochemical CO2 reduction and X-ray tomography measurements with the assistance of L. P.-F. and D. Y. P. K. W. contributed to the simulation of the electrochemical cell. W. D. and C. X. conceived the project. W. D., H. A. A. and C. X. supervised the project. All authors discussed the results and commented on the manuscript.
Conflict of Interest
The authors declare no conflicts of interest.
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Additional details
Funding
- Office of Basic Energy Sciences
- Fuels from Sunlight Hub DE-SC0021266
- Advanced Light Source
- DE-AC02-05CH11231
Dates
- Accepted
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2025-08-01Accepted
- Available
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2025-08-13Published online