Soot Combustion Activity of CeO₂ and CeO₂-ZrO₂ Nanometric Colloidal Sols

Abstract

  Catalytic soot oxidation over dried colloidal sols consisting of CeO₂ and CeO₂-ZrO₂ solid solution was studied before and after loading Ag catalyst. Ag-unloaded CeO₂ exhibited a higher activity than CeO₂-ZrO₂, but their activities after Ag-loading were comparable possibly because Ag activated oxygen responsible for soot oxidation. The CeO₂-ZrO₂ sol exhibited higher thermal stability against sintering than CeO₂ sols and thus retained a higher soot oxidation activity after thermal ageing above 800°C.