Effect of supports over Pd/Fe2O3 on CO oxidation at low temperature

•Pd/γ-Fe2O3 activity for CO oxidation was 2.6 times higher than that of Pd/α-Fe2O3 at 0 °C.•The close contact between Pd and γ-Fe2O3 enhanced the redox recycle between Fe3 + and Fe2 +.•Carbonate absorbed on α-Fe2O3 significantly blocked O2 activation and then inhibited CO oxidation.

Pd/Fe2O3 catalysts were prepared by deposition-precipitation method and investigated for CO oxidation. Compared with Pd/α-Fe2O3, Pd/γ-Fe2O3 exhibited the higher CO oxidation activity, and CO completely oxidation temperature was obtained at 0 °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 γ-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 α-Fe2O3 blocked the oxygen activation which resulted in the low activity of Pd/α-Fe2O3 in CO oxidation.

Graphical abstractDownload high-res image (119KB)Download full-size image