Study of Ag promoted Fe2O3@CeO2 as superior soot oxidation catalysts: The role of Fe2O3 crystal plane and tandem oxygen delivery

In this work, model alpha-Fe2O3 catalysts with different morphologies were synthesized to investigate crystal plane effects on soot oxidation. The results revealed that the electron-rich state of Fe2O3 {113} planes conferred them more surface O-x(-) and thus better catalytic performance than the {014} and {012} planes. Surface grafting of a polycrystalline CeO2 layer onto Fe2O3 gave rise to Fe2O3@CeO2 catalysts with drastically increased oxygen utilization. More importantly, by loading Ag nano-particles on the surface of Fe2O3@CeO2, a tandem oxygen delivery route was opened, resulting in strong O-x(-) generation/regeneration ability and superior low temperature soot oxidation activity. These Ag/Fe2O3@CeO2 catalysts overwhelmed the nano-cubic Ag/CeO2 in both catalyst cost and activity, making them very promising for application in catalyzed gasoline particulate filters (CGPFs).