Oxidation of organics by intermediates of water discharge on IrO2 and synthetic diamond anodes

IrO2 and boron-doped diamond electrodes have been tested by preparative electrolysis of simple model compounds in acid medium. It was confirmed that in oxidation reactions of more complex mechanism than simple electron transfer, these electrodes are active only at potentials of simultaneous oxygen evolution. At IrO2 electrodes, the reaction is mediated by chemisorbed oxygen, probably forming IrO3-type active sites, and yields highly selective oxidation products at low overpotentials and with moderate current efficiency. At diamond electrodes, mediation at high overpotentials is due to physisorbed . OH radicals leading to complete combustion of the organic compound with high current efficiency. (C) 1999 The Electrochemical Society. S1099-0062(98)11-115-X. All rights reserved.