Electrooxidation of the Glycerol Derivative Solketal over Cu-Co Hydroxycarbonates to Enable the Synthesis of Glyceric Acid

The glycerol oxidation reaction (GOR) has high potential in substituting the oxygen evolution reaction (OER) in electrochemical water splitting, enabling the synthesis of value-added organic products. The Cu-rich Cu-Co hydroxycarbonates show high activity in GOR and promote formate production but undergo severe Cu leaching in the presence of deprotonated glycerol. In this work, the electrooxidation of solketal (SOR), acetal-protected glycerol, is explored over a series of Cu-Co hydroxycarbonates, to promote the formation of glycerol-derived C3 products, such as glyceric acid, with faradaic efficiencies of around 70 %, and to limit the Cu leaching from the catalyst. The competition between OER and SOR was evaluated using rotating disk electrodes and differential electrochemical mass spectrometry. Insights into the solketal de-acetalization as a function of potential are obtained using in situ spectroscopic methods. The solketal/OH- ratio influences the reaction selectivity, with oxalate production increasing when 7 m KOH is used instead of 1 m KOH.