Prolonged Stability of Pb-Catalyzed CO2 Electroreduction to Methyl Formate in Acidic Methanol
Electrochemical CO2 reduction from renewable energy is a promising route to mitigate greenhouse gas emissions from waste sources while generating value-added products. CO2 electroreduction in methanol is particularly interesting due to the increased CO2 solubility compared to water and the propensity to form methyl formate, a product absent in aqueous electrolysis. Here, four factors have been identified as critical to achieving prolonged high selectivity for methyl formate production on a Pb cathode in methanol: high pH near the electrode, low bulk pH, low water content, and regeneration of Pb2+ sites. Increasing concentration of the formic acid product was observed to induce a selectivity shift towards hydrogen, which was mitigated by the in-situ conversion of the formic acid to methyl formate via an esterification reaction. Furthermore, co-electrolysis of CO2 with dilute molecular oxygen (4% O2) led to Pb catalyst repair through in-situ surface oxidation. Using CO2 and dilute O2 along with single-pass catholyte flow to maintain a low formic acid concentration, sustained high selectivity for methyl formate was attained at ~60% faradaic efficiency at -20 mA cm-2 for over 72 hours.
- Research Organization:
- Univ. of Louisville, KY (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- FE0031916
- OSTI ID:
- 1970182
- Journal Information:
- ACS Applied Energy Materials, Vol. 6, Issue 4; ISSN 2574-0962
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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