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

Cyclic voltammetry and surface enhanced Raman scattering (SERS) spectra were used over a wide pH range to examine the products of o-aminophenol oxidation on a roughened silver electrode. The results of the study indicated that at least two oxidation products are formed at the stationary potential of the electrode. The major product in alkaline and neutral media was identified as 2,2'-dihydroxy-azobenzene, a linear dimer 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.