Selective electro-oxidation of glycerol to dihydroxyacetone by a non-precious electrocatalyst – CuO

An earth abundant and non-precious electrocatalyst, CuO, is developed for the high selectivity (∼60 %) towards the glycerol electro-oxidation to dihydroxyacetone (DHA) at high current density (3 mA/cm2) under mild basic condition, pH 9. CuO demonstrates the catalytic ability towards the secondary hydroxyl group oxidation of glycerol. However, under strong basic condition, pH 13, DHA would transform to glyceraldehyde (GLAD) spontaneously without applying potential. Thus, under strong basic condition, the glycerol oxidation usually results with other two-carbon and one-carbon products deriving from GLAD oxidation. Based on HPLC, in-situ Raman spectra, and electrochemical studies, the glycerol electro-oxidation pathway was proposed. With this study, the waste by-product from biodiesel plant, glycerol, can be converted to the valuable DHA and formate at the anode while water is split to hydrogen at the cathode. As a result, both biodiesel and water splitting hydrogen generation industries can be beneficial and the system can be more sustainable.