Monodisperse CeO₂ Nanoparticles and Their Oxygen Storage and Release Properties

Abstract

Monodisperse polyhedral nanoparticles (NPs) and nanorods (NRs) of cerium dioxide, CeO2, were synthesized by thermal decomposition of ammonium cerium(IV) nitrate, (NH4)2Ce(NO3)6, at 180 °C in an organic solution of oleylamine (OAm) and/or oleic acid (OA). The 4 nm CeO2 NPs were synthesized in diphenyl ether solution of OAm and OA with the molar ratio of Ce/OAm/OA = 1:3:3, while the 6 nm CeO2 NPs were made in 1-octadecene solution of OAm with Ce/OAm = 1:6. The NRs were formed in 1-octadecene with Ce/OAm/OA = 1:3:1.5. The CeO2 NPs were assembled on γ-Al2O3 via polyvinylpyrrolidone and were annealed at 500 °C under air to remove organic coating. They were well-dispersed on Al2O3 and showed the increased oxygen storage capacity compared to the physical mixture of aggregated CeO2 and γ-Al2O3 powder. The reported CeO2 NPs are promising for oxygen storage and release applications.