ELECTROOXIDATION OF O-AMINOPHENOL STUDIED BY CYCLIC VOLTAMMETRY AND SURFACE-ENHANCED RAMAN-SCATTERING (SERS)

Cyclic voltammetry and surface enhanced Raman scattering (SERS) spectr a were used over a wide pH range to examine the products of o-aminophe nol oxidation on a roughened silver electrode. The results of the stud y indicated that at least two oxidation products are formed at the sta tionary potential of the electrode. The major product in alkaline and neutral media was identified as 2,2'-dihydroxy-azobenzene, a linear di mer formed by N-N coupling of o-aminophenol cation radicals. In acidic solutions the cyclic dimer 3-aminophenoxazone formed by C-N coupling of o-aminophenol cation radicals dominates on the silver electrode.