Role of the TiO2 catalyst under plasma discharge was investigated on the decomposition of CCIF3 in Ar at atmospheric pressure. It was found that the removal rate of CCIF3 increased using a plasma reactor packed with TiO2 compared with a conventional reactor. Carbon oxides and hydrogenated compound were detected even in the absence of oxygen and hydrogen sources. In order to clarify the sources of these products, we tried the measurement of chemical species desorbed from TiO2 by plasma discharge, resulting that molecular oxygen and hydrogen were detected in the gas phase. From these findings, it was suggested that the lattice oxygen and the surface OH on the metal oxides could be activated directly by plasma discharge. (c) 2005 Elsevier B.V. All rights reserved.