Pd/Fe2O3 catalysts were prepared by deposition-precipitation method and investigated for CO oxidation. Compared with Pd/alpha-Fe2O3, Pd/gamma-Fe2O3 exhibited the higher CO oxidation activity, and CO completely oxidation temperature was obtained at 0 degrees C. CO oxidation occurred through the dual sites mechanism, namely CO adsorbed on Pd species and O activation on the support. The close contact between Pd and gamma-Fe2O3 enhanced the redox recycle between Fe3+ and Fe2+ species, which played a decisive role in oxygen activation. The excellent performance in oxygen activation efficiently accelerated the rate-determining step in CO oxidation. The accumulated carbonate and hydrocarbonate species on alpha-Fe2O3 blocked the oxygen activation which resulted in the low activity of Pd/alpha-Fe2O3 in CO oxidation. (C) 2017 Elsevier B.V. All rights reserved.