TY - JOUR

T1 - Brønsted-Evans-Polanyi relationship in oxygen exchange of non-stoichiometric oxides with gas phase

AU - Chizhik, Stanislav A.

AU - Bychkov, Sergey F.

AU - Popov, Mikhail P.

AU - Nemudry, Alexander P.

N1 - Publisher Copyright: © 2019 Elsevier B.V.

PY - 2019/9/1

Y1 - 2019/9/1

N2 - The study of the oxygen exchange of mixed ionic electronic conducting oxides with the gas phase, which determines the efficiency of devices planned to be used in distributed power generation and industrial chemistry is complicated by the strong dependence of their properties on widely varying oxygen nonstoichiometry δ. A new fruitful approach, in which non-stoichiometric oxides are considered as continuous δ-homologous series proposed for solving this problem, requires the development of a new methodology for the collection and analysis of the kinetic data. La 0.6 Sr 0.4 CoO 3- δ (LSC64) δ-homologues were used as examples to demonstrate the novel methodology for studying the kinetics of oxygen exchange by oxygen partial pressure relaxation technique. It includes analysis of the kinetic data in the isostoichiometric cross-section, a non-linear model of relaxation kinetics, a detailed consideration of the mass balance in the reactor, accounting for the particle size distribution in the sample and the response time of the experimental setup. For the continuous series of LSC64 δ-homologues, the Brønsted-Evans-Polanyi relationship is established: the linear correlation of the Gibbs activation energy with the chemical potential of the oxide, as well as the compensation effect between the activation parameters of the equilibrium oxygen exchange rate.

AB - The study of the oxygen exchange of mixed ionic electronic conducting oxides with the gas phase, which determines the efficiency of devices planned to be used in distributed power generation and industrial chemistry is complicated by the strong dependence of their properties on widely varying oxygen nonstoichiometry δ. A new fruitful approach, in which non-stoichiometric oxides are considered as continuous δ-homologous series proposed for solving this problem, requires the development of a new methodology for the collection and analysis of the kinetic data. La 0.6 Sr 0.4 CoO 3- δ (LSC64) δ-homologues were used as examples to demonstrate the novel methodology for studying the kinetics of oxygen exchange by oxygen partial pressure relaxation technique. It includes analysis of the kinetic data in the isostoichiometric cross-section, a non-linear model of relaxation kinetics, a detailed consideration of the mass balance in the reactor, accounting for the particle size distribution in the sample and the response time of the experimental setup. For the continuous series of LSC64 δ-homologues, the Brønsted-Evans-Polanyi relationship is established: the linear correlation of the Gibbs activation energy with the chemical potential of the oxide, as well as the compensation effect between the activation parameters of the equilibrium oxygen exchange rate.

KW - BEP relation

KW - Continuous homologous series

KW - Linear free energy relationship

KW - Non-stoichiometric oxides

KW - Oxygen exchange

KW - Relaxation kinetics

KW - SURFACE EXCHANGE

KW - FREE-ENERGY RELATIONSHIPS

KW - STOICHIOMETRY

KW - MECHANISMS

KW - RELEASE

KW - TRANSITION

KW - COEFFICIENT

KW - KINETICS

KW - PEROVSKITE

KW - DIFFUSION

UR - http://www.scopus.com/inward/record.url?scp=85064253475&partnerID=8YFLogxK

U2 - 10.1016/j.cej.2019.04.056

DO - 10.1016/j.cej.2019.04.056

M3 - Article

AN - SCOPUS:85064253475

VL - 371

SP - 319

EP - 326

JO - Chemical Engineering Journal

JF - Chemical Engineering Journal

SN - 1385-8947

ER -