Paired electrochemical synthesis of formate via oxidation of glycerol and reduction of CO2 in a flow cell reactor

• Published in: Electrochemistry communications Vol. 151; p. 107497
• Main Authors: Vehrenberg, Jan, Baessler, Jonas, Decker, Alexandra, Keller, Robert, Wessling, Matthias
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2023; Elsevier
• Subjects: Electrochemical CO2 reduction; Formate; Glycerol oxidation; Lactate; Paired synthesis; Electrochemical CO2 reduction; Formate; Glycerol oxidation; Lactate; Paired synthesis
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2023.107497

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•Paired electrochemical synthesis of formate via glycerol oxidation and CO2 reduction.•Glycerol oxidation reduces cell voltage and anode potential by 1 V compared to OER.•Concurrent faraday efficiency for formate of 30% and 74% at anode and cathode respectively.•Current density of 50 mA/cm2 in a flow cell reactor.
The conventional anodic oxygen evolution (OER) in electrochemical CO2 reduction (CO2R) needs to be replaced as it accounts for a major share in energy consumption while being a product of little to no value. In this work, we replace OER by glycerol oxidation reaction (GOR) to synthesize products such as formate, lactate and glycolate. Hereby, for the first time, GOR was successfully paired with cathodic CO2R to formate in a flow reactor at a significant current density of 50 mA/cm2 producing value added anode products with a simultaneously reduced cell voltage. Using a porous platinum anode, GOR reduced the anode potential as well as cell potential by ∼1 V compared to OER. We report an anodic Faraday efficiency (FE) of 30% to ∼53% for liquid products, of which lactate dominates. The structure of the electrode has a significant impact on the dominant product as mainly formate is synthesized on a planar electrode, where the cummulated FE for all liquid products is up to 76%. The concurrent FE to formate at cathode and anode reached a values of up to 74% and 30% respectively and 66% and 76%, respectively, considering all value-added products. By successfully pairing GOR with CO2R in a flow cell reactor, this work marks an important step towards energy-efficient and economically viable processes.