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2D Diffusion of Oxygen in Ln10Mo2O21 (Ln = Nd, Ho) Oxides Full article

Conference 22nd International Conference on Solid State Ionics
16-21 Jun 2019 , PyeongChang
Journal Solid State Ionics
ISSN: 0167-2738
Output data Year: 2020, Volume: 346, Article number : 115229, Pages count : 8 DOI: 10.1016/j.ssi.2020.115229
Tags 2D diffusion; 6170N; 6610M; 6630D; 8220P; 8220W; 8610B; Isotope exchange of oxygen; Ln molybdates; Mathematical modeling; Oxygen diffusion
Authors Sadykov Vladislav 1,2 , Shlyakhtina Anna 3 , Sadovskaya Ekaterina 1,2 , Eremeev Nikita 1 , Skazka Valeriy 2,4 , Goncharov Vladimir 1
Affiliations
1 Federal Research Center Boreskov Institute of Catalysis, Akad. Lavrentieva ave. 5, Novosibirsk 630090, Russia
2 Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia
3 Semenov Institute of Chemical Physics RAS, Kosygina st. 4, Moscow 119991, Russia
4 Sobolev Institute of Mathematics SB RAS, Acad. Koptyug ave. 4, Novosibirsk 630090, Russia

Funding (1)

1 Russian Science Foundation 16-13-00112

Abstract: Ln molybdates are promising materials for hydrogen/oxygen separation membranes. This work aims at elucidating features of oxygen transport in Ln10Mo2O21 (Ln = Nd, Ho) oxides using novel 2D diffusion models. Nd10Mo2O21 and Ho10Mo2O21 were synthesized by the mechanical activation followed by sintering in the 1600–1650 °C temperature range and characterized by XRD as a complex rhombohedral phase and fluorite one, respectively. Oxygen transport features were studied by the oxygen isotope heteroexchange with C18O2 in a flow reactor using temperature-programmed and isothermal modes. According to numerical analysis, isotope exchange in Ln10Mo2O21 cannot be described by a single diffusion coefficient, which is explained by nonuniformity of the oxygen diffusion pathways. The mathematical model including equations for a faster diffusion along grain boundaries and a slower diffusion within grain bulk (2D diffusion model) gives the best fit. The same accuracy was achieved using the model including 2D diffusion and exchange between grain bulk oxygen forms with different M-O bonds strength. The values of oxygen tracer diffusion coefficient are ~10−7–10−6 cm2/s and ~10−11–10−8 cm2/s at 700 °C along grain boundaries and within grain bulk, respectively. Hence, new 2D models were developed to describe oxygen diffusion in polycrystalline oxides. A fast oxygen diffusion demonstrated for Ln10Mo2O21 oxides makes them promising for design of hydrogen/oxygen separation membranes. © 2020 Elsevier B.V.
Cite: Sadykov V. , Shlyakhtina A. , Sadovskaya E. , Eremeev N. , Skazka V. , Goncharov V.
2D Diffusion of Oxygen in Ln10Mo2O21 (Ln = Nd, Ho) Oxides
Solid State Ionics. 2020. V.346. 115229 :1-8. DOI: 10.1016/j.ssi.2020.115229 WOS Scopus РИНЦ AN OpenAlex
Dates:
Submitted: Jul 17, 2019
Accepted: Jan 16, 2020
Published online: Jan 21, 2020
Published print: Mar 1, 2020
Identifiers:
Web of science: WOS:000517851600025
Scopus: 2-s2.0-85078570565
Elibrary: 43232119
Chemical Abstracts: 2020:153212
OpenAlex: W3000758645
Citing:
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Scopus 6
Web of science 7
Elibrary 6
OpenAlex 7
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