Enabling Stable and Salt-Free Formic Acid Production via Reactive Interface Optimization in Forward-Bias Bipolar-Membrane CO <sub>2</sub> Electrolyzers
High Resolution Image Download MS PowerPoint Slide Electrochemical conversion of CO 2 to liquid products is limited by parasitic reactions that consume products and destabilize operation. Here, we show that salt-free formic acid synthesis in a forward-bias bipolar-membrane CO 2 electrolyzer is governed by a coupled reaction-transport instability driven by parasitic anode formic acid oxidation. Operando mass spectrometry reveals that this process proceeds through CO-mediated poisoning, identifying catalyst tolerance to CO as a key descriptor of anode selectivity. Among the catalysts examined, PtRu/C preferentially promotes hydrogen oxidation over formic acid oxidation. Coupling this catalyst with transport-interface engineering improves product removal, enhances Faradaic and energy efficiency, and enables stable operation at 200 mA/cm 2 for 190 h with a voltage decay of 0.64 mV/h. Techno-economic analysis indicates an 18% reduction in minimum selling price and highlights product concentration as the dominant cost lever. These results establish a general framework for suppressing product oxidation in liquid-product electrolyzers.
Authors
- K.C. Neyerlin (ORCID: https://orcid.org/0000-0002-6753-9698)
- Arthur Jeremy Kropf (ORCID: https://orcid.org/0000-0002-3329-4493)
- Carly Byron (ORCID: https://orcid.org/0000-0002-1716-5659)
- Fry Intia
- Magali Ferrandon (ORCID: https://orcid.org/0000-0003-2544-6466)
- Leiming Hu (ORCID: https://orcid.org/0000-0003-2999-1576)
- I. Berry (ORCID: https://orcid.org/0000-0002-0886-3252)
- Jacob A. Wrubel (ORCID: https://orcid.org/0000-0002-3347-0768)
- James L. Young (ORCID: https://orcid.org/0000-0001-7291-0079)
- Deborah J. Myers (ORCID: https://orcid.org/0000-0001-9299-3916)
- David A. Cullen (ORCID: https://orcid.org/0000-0002-2593-7866)
- Recep Kaş (ORCID: https://orcid.org/0000-0003-0508-5894)
- Zhe Huang
- Carlos Baez-Cotto
- Matthew E. Sweers (ORCID: https://orcid.org/0000-0002-4040-6502)
- Kimberly S. Reeves
- Luke Cherniack
- Piyush Kumar
Institutions
- Argonne National Laboratory (US)
- Oak Ridge National Laboratory (US)
- Center for NanoScience (DE)
- Museum of the Rockies (US)
- Catalytic Materials (United States) (US)
- Center for Nanophase Materials Sciences
Publication Details
- Journal
- ACS Energy Letters
- Published
- 2026-06-30
- DOI
- https://doi.org/10.1021/acsenergylett.6c00932
- Primary Topic
- CO2 Reduction Techniques and Catalysts
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- U.S. Department of Energy
- University of Chicago
- Office of Fossil Energy
- Office of Science
- Office of Energy Efficiency and Renewable Energy
- Office of Nuclear Energy
- Division of Materials Research
- Argonne National Laboratory
- National Renewable Energy Laboratory