TY - JOUR

T1 - Engineering of oxygen pathways for better oxygen permeability in Cr-substituted Ba2In2O5 membranes

AU - Widenmeyer, Marc

AU - Wiegers, Katharina Sophia

AU - Chen, Guoxing

AU - Yoon, Songhak

AU - Feldhoff, Armin

AU - Weidenkaff, Anke

N1 - Funding Information: The authors thank Dr. Mauro Coduri (ESRF, Grenoble) and Prof. Dr. Marco Scavini (University of Milan) for their help as well as the ESRF, Grenoble, France for the granted beam time and financial support of experiment CH-5342 . We also thank Samir Hammoud (Max Planck Institute for Intelligent Systems, Stuttgart) for the hot gas extraction measurements, M.Sc. Cora Bubeck (Technische Universität Darmstadt) for collection of SEM images, and M.Sc. Zhijun Zhao (Leibniz University of Hannover) for his assistance during the permeation experiments. This work was supported by the Federal Ministry of Education and Research of Germany in the framework of the Kopernikus projects for the Energiewende within the project PiCK (project number: 03SFK2S3B ) and the Vector Stiftung (project number: 2015-044 ).

PY - 2020/2/1

Y1 - 2020/2/1

N2 - Ba2In2O5 is a mixed ionic–electronic conducting (MIEC) ceramic-based material offering a large number of oxygen vacancies to become an alternative material for oxygen separation membranes from gas mixtures or even a CO2 plasma. This material was selected as model system to deeper analyze the structure-property relations, while making use of a promising structure stability. In this study, partial substitution of In3+ by Cr3+ yielded single-phase Ba2In2–xCrxO5–δ (x = 0, 0.2, 0.25). This forced an altered arrangement of the oxygen vacancies and a structural change from orthorhombic (Ibm2) to tetragonal (I4cm). The highest oxygen permeability of P(O2) = 1.4 ± 0.1 mL min−1·cm−2·mm at 1223 K among all tested samples was obtained for x = 0.2. A precise adjustment of the degree of oxygen vacancy ordering and the unit cell volume in this material reduced the activation energy EA and enhanced the self-diffusion coefficient D0 of the oxygen ions boosting the oxygen permeability as demonstrated by the superior oxygen permeability at lower temperatures (~1000 K), still reaching an oxygen permeability of P(O2) = 0.72 ± 0.04 mL min−1·cm−2·mm at 773 K. This concept seems plausible for an adaption to other structurally related membrane materials.

AB - Ba2In2O5 is a mixed ionic–electronic conducting (MIEC) ceramic-based material offering a large number of oxygen vacancies to become an alternative material for oxygen separation membranes from gas mixtures or even a CO2 plasma. This material was selected as model system to deeper analyze the structure-property relations, while making use of a promising structure stability. In this study, partial substitution of In3+ by Cr3+ yielded single-phase Ba2In2–xCrxO5–δ (x = 0, 0.2, 0.25). This forced an altered arrangement of the oxygen vacancies and a structural change from orthorhombic (Ibm2) to tetragonal (I4cm). The highest oxygen permeability of P(O2) = 1.4 ± 0.1 mL min−1·cm−2·mm at 1223 K among all tested samples was obtained for x = 0.2. A precise adjustment of the degree of oxygen vacancy ordering and the unit cell volume in this material reduced the activation energy EA and enhanced the self-diffusion coefficient D0 of the oxygen ions boosting the oxygen permeability as demonstrated by the superior oxygen permeability at lower temperatures (~1000 K), still reaching an oxygen permeability of P(O2) = 0.72 ± 0.04 mL min−1·cm−2·mm at 773 K. This concept seems plausible for an adaption to other structurally related membrane materials.

KW - BaInO

KW - Brownmillerite

KW - Cr-substitution

KW - Membrane

KW - Oxygen separation

UR - http://www.scopus.com/inward/record.url?scp=85074015407&partnerID=8YFLogxK

U2 - 10.1016/j.memsci.2019.117558

DO - 10.1016/j.memsci.2019.117558

M3 - Article

AN - SCOPUS:85074015407

VL - 595

JO - Journal of membrane science

JF - Journal of membrane science

SN - 0376-7388

M1 - 117558

ER -