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An electrical conductivity relaxation study of oxygen transport in samarium doped ceria

Gopal, Chirranjeevi Balaji and Haile, Sossina M. (2014) An electrical conductivity relaxation study of oxygen transport in samarium doped ceria. Journal of Materials Chemistry A, 2 (7). pp. 2405-2417. ISSN 2050-7488. https://resolver.caltech.edu/CaltechAUTHORS:20140214-105250564

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Abstract

The efficacy of the electrical conductivity relaxation (ECR) technique for investigating the oxygen transport properties of mixed conducting oxides has been evaluated. Fifteen mol% samarium doped ceria (SDC15), for which approximate values of the two principal transport properties, bulk oxygen diffusivity, D_(Chem), and surface reaction rate constant, kS, can be found in the literature, was chosen as the benchmark material against which to validate the methodology. Measurements were carried out at temperatures between 750 and 850 °C and over a wide range of oxygen partial pressures. An unexpectedly high p-type electronic transference number enabled ECR measurements under oxidizing conditions. A systematic data analysis procedure was developed to permit reliable extraction of the kinetic parameters even in the general case of simultaneous bulk and surface limitation. The D_(Chem) from this study showed excellent qualitative and quantitative agreement with expected values, falling in the range from ~2 × 10^(−5) to 2 × 10^(−4) cm^2 s^(−1). The surface reaction constant under H_2–H_2O mixtures also showed good agreement with literature results. Remarkably, this value increased by a factor of 40 under mixtures of CO–CO_2 or O_2–Ar. This observation suggests kinetic advantages for production of CO rather than H_2 in a two-step solar-driven thermochemical process based on samarium doped ceria.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://pubs.rsc.org/en/Content/ArticleLanding/2014/TA/c3ta13404kPublisherArticle
http://dx.doi.org/10.1039/C3TA13404K DOIArticle
ORCID:
AuthorORCID
Haile, Sossina M.0000-0002-5293-6252
Additional Information:© 2014 The Royal Society of Chemistry. Received 28 Aug 2013, Accepted 20 Dec 2013. First published online 10 Jan 2014. This material is based upon work supported by the National Science Foundation under Grant no. CBET-1038307.
Funders:
Funding AgencyGrant Number
NSFCBET-1038307
Issue or Number:7
Record Number:CaltechAUTHORS:20140214-105250564
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140214-105250564
Official Citation:An electrical conductivity relaxation study of oxygen transport in samarium doped ceria Chirranjeevi Balaji Gopal and Sossina M. Haile J. Mater. Chem. A, 2014, 2, 2405-2417 DOI: 10.1039/C3TA13404K
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43836
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:18 Feb 2014 15:44
Last Modified:03 Oct 2019 06:11

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