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DOE OSTI · 3796125

Controlled Acidity Gradients Enable CO 2 Reduction to Formic Acid (Not Formate) by Molecular Electrocatalysts

Fernández, Sergio [University of North Carolina at Chapel Hill, NC (United States)] (ORCID:0000000216208514)·Fernandez, Pablo [University of North Carolina at Chapel Hill, NC (United States)]·Arnoff, Amanda I. [University of Pennsylvania, Philadelphia, PA (United States)]·Scholer, Elizabeth A. [University of North Carolina at Chapel Hill, NC (United States)]·Montgomery, Charlotte L. [University of North Carolina at Chapel Hill, NC (United States)]·Dempsey, Jillian L. [University of North Carolina at Chapel Hill, NC (United States)] (ORCID:0000000294594166)·Mallouk, Thomas E. [University of Pennsylvania, Philadelphia, PA (United States)] (ORCID:0000000345994208)·Lopez, René [University of North Carolina at Chapel Hill, NC (United States)]·Miller, Alexander J. M. [University of North Carolina at Chapel Hill, NC (United States)] (ORCID:0000000193903951)
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Abstract

Neutral or basic conditions are commonly required for the selective electrochemical reduction of CO 2 , leading to the accumulation of carbonate salts and the generation of formate rather than formic acid. A generalizable strategy for obtaining formic acid (not formate) in the electroreduction of CO 2 with molecular catalysts is introduced, based on controlling acidity gradients using a dual-electrolyte cell with a proton-exchange membrane. This approach uses anodic water oxidation as the source of protons and electrons for CO 2 reduction to formic acid, while mitigating H 2 evolution near the cathode and avoiding carbonate formation. Mechanistic studies, including systems modeling, provide insight into the origin of the formic acid selectivity and guide the broader implementation of this strategy in molecular electrocatalysis for CO 2 utilization.

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Fernández, Sergio [University of North Carolina at Chapel Hill, NC (United States)] (ORCID:0000000216208514), Fernandez, Pablo [University of North Carolina at Chapel Hill, NC (United States)], Arnoff, Amanda I. [University of Pennsylvania, Philadelphia, PA (United States)], Scholer, Elizabeth A. [University of North Carolina at Chapel Hill, NC (United States)], Montgomery, Charlotte L. [University of North Carolina at Chapel Hill, NC (United States)], Dempsey, Jillian L. [University of North Carolina at Chapel Hill, NC (United States)] (ORCID:0000000294594166), Mallouk, Thomas E. [University of Pennsylvania, Philadelphia, PA (United States)] (ORCID:0000000345994208), Lopez, René [University of North Carolina at Chapel Hill, NC (United States)], Miller, Alexander J. M. [University of North Carolina at Chapel Hill, NC (United States)] (ORCID:0000000193903951). 2026-07-17. Controlled Acidity Gradients Enable CO 2 Reduction to Formic Acid (Not Formate) by Molecular Electrocatalysts. https://doi.org/10.1021/acscentsci.6c00571

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