In this work the application of a redox treatment consisting of a high-temperature reduction with 5%H-2/Ar in the range 950-1075 degrees C for 0.5-3 h followed by mild oxidation at 550 degrees C with 5%O-2/He was evaluated as a tool for improving the catalytic performance of Ce0.5Zr0.5O2 mixed oxide in the combustion of chlorinated compounds. Structural, morphological and physico-chemical changes caused by the redox treatment were analysed by X-ray diffraction, Raman spectroscopy. BET measurements, NH3-temperature programmed desorption, temperature programmed reduction with hydrogen, and oxygen chemisorption. Interestingly, after reduction at a temperature as high as 1050 degrees C during at least 1.5 h, a substantially enhanced redox behaviour was noticed which resulted in a significant promotion of the catalytic activity in comparison with the unmodified parent sample. Hence, the value of temperature of half conversion at 30,000 h(-1) decreased from 300 to 275 degrees C for the combustion of 1,2-dichloroethane, which was selected as a model chlorinated feed. This active performance was assigned to the formation of a new kappa-CeZrO4 phase after redox aging characterised by a markedly increased capacity of providing active oxygen species at low temperatures. For comparative purposes two additional Ce0.5Zr0.5O2 samples calcined at 750 and 1000 degrees C were also characterised and catalytically tested. (c) 2010 Published by Elsevier B.V.