Elucidating the Oxygen Storage-Release Dynamics in Ceria Nanorods by Combined Multi-Wavelength Raman Spectroscopy and DFT
Marc Ziemba, M. V. Ganduglia-Pirovano, Christian Heß
Abstract
The oxygen storage-release dynamics in ceria nanorods is elucidated by using a combination of in situ multi-wavelength Raman spectroscopy and density functional theory calculations. Ceria nanorods exposing CeO2(100) and CeO2(110) facets are shown to be characterized by highly facet-dependent properties regarding molecular oxygen activation and decomposition as well as lattice oxygen dynamics. Temperature-dependent Raman results show that oxygen is stored in the form of peroxide species on the (100) facets, which are then released as gaseous oxygen, whereas lattice oxygen is involved with the (110) facets. On the latter, peroxide species first decompose into oxygen atoms that heal vacant lattice oxygen sites before being released as gaseous oxygen. The exposure of different facets makes ceria nanorods an interesting material for catalytic applications, because they allow the use of a mixture of oxygen storage-release functions, as well as their synergistic interactions, in a single system.