We studied the oxidation of phenol by HO2- ions obtained from the oxygen reduction reaction (ORR) on pyrolytic graphite and on Ni0.3Co2.7O4 spinel oxide in 1M KOH at 25 degreesC. Phenol degradation was achieved by using the controlled potential electrolysis of saturated O2 solutions under batch and laminar flow conditions. In both electrodes, the electro- generation of HO2- occurs between -0.2 V and -0.4V, with the graphite being more efficient than the Ni0.3Co2.7O4 electrode. The phenol degradation conversions for the batch electrolysis were 32% on graphite and 21% on the oxide, whereas with the flow mode they were 7% and 22% respectively.