Selective Electro-oxidation of Alcohols to the Corresponding Aldehydes in Aqueous Solution via Cu(III) Intermediates from CuO Nanorods

Electrochemical oxidation using renewable energy is an attractive strategy that provides a sustainable and mild approach for biomass transformation. Herein, the electrocatalytic oxidation of furfuryl alcohol in an aqueous solution was investigated using CuO nanorods. Two kinds of CuIII intermediates, namely, (CuO2)− and (Cu2O6)6–, were detected on the surface of the working electrode. (Cu2O6)6–, generated in the potential range of 1.35–1.39 V versus the reversible hydrogen electrode (RHE), induced the oxidation of furfuryl alcohol to furaldehyde with a yield of ≥98%. (CuO2)−, generated at a potential greater than 1.39 V versus RHE, which led to the oxidation of furfuryl alcohol to 2-furoic acid with a yield of ≥99%. Furthermore, the CuIII-catalyzed system exhibited a measure of universal applicability, wherein (Cu2O6)6– and (CuO2)− induced the highly selective electro-oxidation of benzyl alcohol, vanillyl alcohol, and 4-pyridinemethanol to yield the corresponding aldehydes and acids, respectively.