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
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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/ | ||||||||||||||||||
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Document Type: | Article | ||||||||||||||||||
Additional Information: | HGF Virtuel Institute SolarSynGas | ||||||||||||||||||
Title: | Surface controlled reduction kinetics of nominally undoped polycrystalline CeO2 | ||||||||||||||||||
Authors: |
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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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