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A piezomicrobalance system for high-temperature mass relaxation characterization of metal oxides: A case study of Pr-doped ceria

Simons, Philipp and Ji, Ho-Il and Davenport, Timothy C. and Haile, Sossina M. (2017) A piezomicrobalance system for high-temperature mass relaxation characterization of metal oxides: A case study of Pr-doped ceria. Journal of the American Ceramic Society, 100 (3). pp. 1161-1171. ISSN 0002-7820. https://resolver.caltech.edu/CaltechAUTHORS:20170105-145307247

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Abstract

A system for mass relaxation studies based on a gallium phosphate piezocrystal microbalance has been developed, built, and successfully used to characterize a representative mixed ionic and electronic conducting material. The apparatus is constructed to achieve reactor gas exchange times as short as 2 seconds and temporal resolution in mass measurement of 0.1 seconds. These characteristics enabled evaluation of mass relaxations that occurred on the 6 seconds time scale. Proof of concept for materials characterization capabilities of the system was carried out using 10% praseodymium-doped cerium oxide (PCO), a material that undergoes, at selected temperatures and oxygen partial pressures, changes in mass but not in conductivity. Thin films were deposited on the piezocrystals via pulsed laser deposition (PLD). Mass relaxation curves were collected at 700°C upon application of a small step change in oxygen partial pressure, p_(O_2). Using two different films, the surface reaction constant, k_S, was obtained over the p_(O_2) range from 10^(−4) to 0.1 atm. Its value is found to vary between 9.7 × 10^(−6) and 1.7 × 10^(−4) cm/s, displaying a power law dependence on p_(O_2), with a law exponent of 0.67 ± 0.02, as averaged over the two sets of results. This steep dependence of k_S on p_(O_2) is surprisingly independent of a change in dominant defect type within the p_(O_2) range of measurement.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1111/jace.14652DOIArticle
http://onlinelibrary.wiley.com/doi/10.1111/jace.14652/abstractPublisherArticle
ORCID:
AuthorORCID
Ji, Ho-Il0000-0002-6194-991X
Haile, Sossina M.0000-0002-5293-6252
Additional Information:© 2016 The American Ceramic Society. Received: 18 July 2016. Accepted: 21 October 2016. Version of record online: 21 December 2016. Funding of this project through the California Institute of Technology EAS Discovery Funds Program is gratefully acknowledged. Support for T.C.D. was provided by an EERE Postdoctoral Research Award. The authors thank Haemin Paik and Anupama Khan for assisting with AFM measurements, as well as Fan Yang from the Joint Center for Artificial Photosynthesis for assistance with ALD. The authors furthermore thank the Caltech GPS Division Analytical Facility and NUANCE at Northwestern University for providing access to SEM and AFM instrumentation. P.S. thanks Prof. Aldo Steinfeld for supporting his research visit to the California Institute of Technology.
Funders:
Funding AgencyGrant Number
Caltech Division of Engineering and Applied ScienceUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Subject Keywords:cerium oxide/doped cerium oxide, kinetics, oxides, piezoelectric materials/properties, surface
Issue or Number:3
Record Number:CaltechAUTHORS:20170105-145307247
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170105-145307247
Official Citation:Simons P, Ji H-I, Davenport TC, Haile SM. A piezomicrobalance system for high-temperature mass relaxation studies of metal oxides: A case study of Pr-doped ceria. J Am Ceram Soc. 2017;100:1161–1171
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73282
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:06 Jan 2017 17:03
Last Modified:03 Oct 2019 16:26

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