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Surface controlled reduction kinetics of nominally undoped polycrystalline CeO2

Knoblauch, Nicole and Dörrer, Lars and Fielitz, Peter and Schmücker, Martin and Borchardt, Günter (2015) Surface controlled reduction kinetics of nominally undoped polycrystalline CeO2. Physical Chemistry Chemical Physics (17), pp. 5849-5860. Royal Society of Chemistry. DOI: 10.1039/c4cp05742b ISSN 1463-9076

Full text not available from this repository.

Abstract

Ceria is an interesting material for high temperature redox applications like solar-thermal splitting of CO2 and H2O. Technical implementation and reactor design for solar-thermal redox-based fuel generation requires reliable data for the chemical surface exchange coefficient and the chemical diffusivity of oxygen. The results of thermogravimetric relaxation experiments and equilibrium oxygen isotope exchange experiments with subsequent depth profiling analysis suggest that the reduction reaction of even dense samples of pure ceria (1 mm thickness, 93% of theoretical density) with a grain size of about 20 mm is surface reaction controlled. The chemical surface exchange coefficient exhibits a negative apparent activation energy (-64 kJ mol-1). This finding is corroborated by similar data from literature for the tracer surface exchange coefficient. The structure of the derived expression for the apparent activation energy further suggests that the chemical surface exchange coefficient should show only a very weak dependence on temperature for ceria doped with lower valence cations.

Item URL in elib:https://elib.dlr.de/99398/
Document Type:Article
Additional Information:HGF Virtuel Institute SolarSynGas
Title:Surface controlled reduction kinetics of nominally undoped polycrystalline CeO2
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Knoblauch, NicoleWF-KSWUNSPECIFIED
Dörrer, LarsTechnische Universität Clausthal, Institut für MetallurgieUNSPECIFIED
Fielitz, PeterTechnische Universität Clausthal, Institut für MetallurgieUNSPECIFIED
Schmücker, MartinDLRUNSPECIFIED
Borchardt, GünterTechnische Universität Clausthal, Institut für MetallurgieUNSPECIFIED
Date:17 January 2015
Journal or Publication Title:Physical Chemistry Chemical Physics
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
DOI :10.1039/c4cp05742b
Page Range:pp. 5849-5860
Publisher:Royal Society of Chemistry
ISSN:1463-9076
Status:Published
Keywords:Ceria, solar-thermal splitting, surface reaction
HGF - Research field:Energy
HGF - Program:Renewable Energies
HGF - Program Themes:Solar Fuels
DLR - Research area:Energy
DLR - Program:E SW - Solar and Wind Energy
DLR - Research theme (Project):E - Solar Fuels
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > Keramische Strukturwerkstoffe
Deposited By: Knoblauch, Nicole
Deposited On:18 Nov 2015 09:35
Last Modified:06 Sep 2019 15:16

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