| AVS 62nd International Symposium & Exhibition | |
| In-Situ Spectroscopy and Microscopy Focus Topic | Tuesday Sessions |
| Session IS+AS+SS-TuA |
| Session: | Environmental TEM Studies for Catalytic and Energy Materials |
| Presenter: | Zili Wu, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Ceria is best known for its excellent redox property that makes it an important component in the three-way catalyst for auto exhaust cleanup. This is a result of its high oxygen storage capacity associated with the rich oxygen vacancy and low redox potential between Ce3+ and Ce4+ cations. Equally interesting yet less is known about ceria is its versatile acid-base properties. Either as a standalone catalyst, a modifier or a support, ceria and ceria-based catalysts can catalyze the transformation of a variety of organic molecules that makes use of the acid-base as well as the redox properties of ceria.
Recent advances in nanomaterials synthesis make it possible to achieve nanocrystals with crystallographically defined surface facets and high surface area, which can be considered as ideal model systems for catalytic studies under realistic conditions. In this work, I will showcase how we can make use of ceria nanoshapes as model systems to gain molecular level understanding of the shape effect on both redox and acid-base properties and catalysis of ceria nanocrystals via in situ IR and Raman spectroscopy. Insights have been gained into how the surface structure of ceria catalyst affects profoundly its redox and acid-base properties and consequently the catalytic behaviors. It is suggested that the surface structure of ceria controls the catalytic performance through the combination of various factors including structure-dependent surface sites geometry, lattice oxygen reactivity, surface vacancy formation energy, defect sites, and acid-base property on ceria.
Acknowledgements: This work was supported by Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, U.S. Department of Energy. A portion of the work was supported by the Center for Understanding & Control of Acid Gas-Induced Evolution of Materials for Energy (UNCAGE-ME), an Energy Frontier Research Center funded by DOE, Office of Science, Basic Energy Sciences. The IR and Raman work were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.