Zirconium oxide catalysts for manufacturing dichloropentafluoropropanes (HCFC-225ca and 225cb) by the reaction of dichlorofluoromethane with tetrafluoroethylene were investigated. When activated by elemental fluorine or dichlorodifluoromethane, zirconium oxide exhibited high catalytic activity and better selectivity toward HCFC-225s in the reaction at ordinary temperatures. XRD and XPS analyses revealed that the fluorine-activated zirconium oxide catalyst is a mixture of zirconium oxide, zirconium tetrafluoride, and partially fluorinated zirconium oxide. These results suggest that zirconium oxide underwent a surface fluorination reaction, resulting in enhanced catalytic activity as a Lewis acid. (C) 2009 Elsevier B.V. All rights reserved.