Co oxide doped carbon aerogel (Co/CA) was prepared, characterised by several techniques, and tested for heterogeneous oxidation of phenol in aqueous solution using oxone as an oxidant. For a comparison, homogeneous oxidation of phenol in Co2+/oxone was also investigated. It was found that homogeneous oxidation of phenol using Co2+/oxone was more effective than Co2+/H2O2 and homogeneous oxidation was faster than heterogeneous Co/CA-oxone. Heterogeneous oxidation of phenol in Co/CA-oxone system followed first order kinetics and the activation energy of the heterogeneous system was estimated to be 62.9 kJ/mol. Several factors influencing phenol degradation in the heterogeneous oxidation were studied. Co/CA loading played a more important role in phenol degradation than oxone concentration, and the presence of other organics in solution resulted in a lower phenol oxidation. (C) 2011 Elsevier B.V. All rights reserved.