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 ele ctrolysis of simple model compounds in acid medium. It was confirmed that i n oxidation reactions of more complex mechanism than simple electron transf er, these electrodes are active only at potentials of simultaneous oxygen e volution. At IrO2 electrodes, the reaction is mediated by chemisorbed oxyge n, probably forming IrO3-type active sites, and yields highly selective oxi dation products at low overpotentials and with moderate current efficiency. At diamond electrodes, mediation at high overpotentials is due to physisor bed . OH radicals leading to complete combustion of the organic compound wi th high current efficiency. (C) 1999 The Electrochemical Society. S1099-006 2(98)11-115-X. All rights reserved.