A highly efficient catalyst has been produced by immobilizing a biomimetic iron-porphyrin complex onto SiO2. The catalyst was found to be highly efficient on the degradation of pentachlorophenol (PCP) achieving 100% of PCP decomposition within 2.5 h. Furthermore, complete dechlorination of the initial added PCP substrate was accomplished at the end of the reaction time. Dechlorination proceeded even after PCP was fully decomposed. The initial and main final metabolites of PCP decomposition were identified and a general catalytic mechanism is proposed. (C) 2010 Elsevier B.V. All rights reserved.