Oxidizing Ethanol and 2-Propanol by Hypochlorous Acid Generated from Chloride Ions on H_xWO₃ Photoelectrodes

Abstract

Photoelectrochemically oxidizing aqueous chloride electrolytes (1 M NaCl, pH 3) to hypochlorous acid proceeds on H x WO3 semiconducting photoelectrodes using 405 nm illumination at 100 mW/cm2 with 1.0 V versus Ag/AgCl constant potential chronoamperometry. The hypochlorous acid serves as an oxidation agent upon adding 100 mM ethanol or 2-propanol into the solution. 1H NMR spectroscopy shows that 90% of the charge passed results in oxidized products (acetaldehyde and acetic acid or acetone). Chemically oxidizing ethanol by calcium hypochlorite shows that both light and the H x WO3 surface enhance the reaction rate.