Selective Electro-oxidation of Alcohols to the Corresponding Aldehydes in Aqueous Solution via Cu(III) Intermediates from CuO Nanorods
Zhiyong Fang, Peili Zhang, Mei Wang, Fusheng Li, Xiujuan Wu, Ke Fan, Licheng Sun
Abstract
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.