@article{c35267b3c2a041d7b306a8b290a45e25,
title = " In-situ IR spectroscopy as a probe of oxidation/reduction of Ce in nanostructured CeO 2 ",
abstract = " The redox properties of CeO 2 are crucial in its applications in a wide range of catalytic processes. In the present research, in-situ IR spectroscopy is shown to be a viable and convenient method for the characterization of the oxidation state of Ce by monitoring the spin-orbit transition in Ce 3+ ( 2 F 5/2 → 2 F 7/2 ) at ∼2147 cm −1 . By monitoring this transition in CeO 2 nanorods, the apparent activation energy for the production of oxygen vacancies that accompany the formation of Ce 3+ has been determined and is shown to be lower for reduction with cyclohexene than with hydrogen. The bi-exponential kinetics for the formation of oxygen vacancies in CeO 2 nanorods is discussed. An application of this method to real time monitoring of the oxidation state of Ce in the oxidation of cyclohexene on vanadia supported on ceria is presented as an example of how this method can be used as an operando probe of reaction mechanisms. ",
keywords = "Ce, IR spectroscopy, Kinetics, Nanostructured CeO, Oxygen vacancies",
author = "Weiqiang Wu and Savereide, {Louisa Marie} and Justin Notestein and Eric Weitz",
note = "Funding Information: This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy (Award No. DE-FG02-03-ER15457 ). The in-situ IR measurements have been performed in the Clean Catalysis Facility of the Northwestern University Center for Catalysis and Surface Science supported by a grant from the DOE ( DE-SC0001329 ). The electron microscopy images were collected in the EPIC facility of Northwestern University{\textquoteright}s NU ANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SH y NE) Resource ( NSF ECCS-1542205 ); the MRSEC program ( NSF DMR-1720139 ) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. This work also made use of the J.B.Cohen X-ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-1720139) at the Material Research Center of Northwestern University and the Soft and Hybrid Nanotechology Experimental Resource (NSF ECCS-1542205). We gratefully acknowledge Dr. James A. McCarthy for providing us with ALD prepared samples of vanadia supported on ceria and also acknowledge Professor Kenneth Poeppelmeier and Professor Peter Stair for their assistance with the preparation of these samples. Publisher Copyright: {\textcopyright} 2018 Elsevier B.V.",
year = "2018",
month = jul,
day = "1",
doi = "10.1016/j.apsusc.2018.03.083",
language = "English (US)",
volume = "445",
pages = "548--554",
journal = "Applied Surface Science",
issn = "0169-4332",
publisher = "Elsevier",
}