Modification of CeO2 on the redox property of Fe2O3

The modifications of CeO2 on the reduction behavior, oxygen storage capacity (OSC), and redox stability of Fe2O3 were investigated. Combination of Fe2O3 with CeO2 strongly improved the low-temperature reducibility of both Fe2O3 and CeO2, evidencing an obvious interaction between cerium and iron oxides during the H-2-TPR process. Most of the Fe3+ in single Fe2O3 cannot be restored by the re-oxidation step (OSC step) after the TPR testing, which resulted in a serious decrease in the OSC. On the other hand, the presence of CeO2 significantly enhanced the redox property of Fe2O3: more iron (III) ions were observed in the recycled CeO2/Fe2O3 mixture (Ce/Fe=1/4, labeled Ce20Fe80 sample), and the OSC was obviously improved by the redox treatment. After the first TPR/OSC cycle, the reduction behavior of the recycled Ce20Fe80 sample is highly reversible, indicating good redox stability. This is attributed to the formation of perovskite-type CeFeO3 with excess CeO2, Fe2O3 and Fe in the recycled Ce20Fe80 sample. (C) 2012 Elsevier B.V. All rights reserved.