The redox performance of pure iron oxide (Fe(2)O(3)) and iron oxide modified with ceria (CeO(2)) and/or zirconia (ZrO(2)) as an oxygen carrier was investigated for hydrogen (H(2)) production through a methane-steam redox process. The addition of both CeO(2) and ZrO(2) were found to be a more effective modification of Fe(2)O(3) than the addition CeO(2) or ZrO(2) alone. It was found that the reducibility of Fe(2)O(3) was enhanced by CeO(2) and the thermal stability of Fe(2)O(3) was improved by ZrO(2). These results, therefore, led to the conclusion of the synergistic effect in the Fe(2)O(3)-CeO(2)-ZrO(2) mixed oxide. As a result, both the redox activity and the thermal stability were significantly improved, and increases in H(2) yield and purity could be maintained by the modification. The redox temperature was found to have a significant effect on redox performance. The production of H(2) was considerably improved when the redox temperature was increased from 650 to 750 degrees C. The ZrO(2) concentration in Fe(2)O(3)-CeO(2)-ZrO(2) mixed oxide samples was also found to influence performance with the highest H(2) yield observed at a ZrO(2) concentration of 75 wt.%. Although all materials tested showed a reduction in surface area in the first redox cycle, the change in surface area in subsequent cycles was found to be smaller and the yield of H(2) could be maintained at a constant level over a longer period for the mixed oxide containing 75 wt.% ZrO(2). Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.