Formation and migration of oxygen vacancies in La1−xSrxCo1−yFeyO3−δperovskites: insight from ab initio calculations and comparison with Ba1−xSrxCo1−yFeyO3−δ

Mastrikov, Yuri A.; Merkle, Rotraut; Kotomin, E. A.; Kuklja, Maija M.; Maier, Joachim

doi:10.1039/c2cp43557h

Cited by 121 publications

(109 citation statements)

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“…O is involved in the rds: either in the final incorporation step of the atomic oxygen species (for LSM 10 ), or by assisting in the dissociation of the O-O bond (LSCF, BSCF 9,12 2 . Furthermore, protonation offers an additional possibility to facilitate the O-O dissociation in steps (T) and (U) by preceding proton and electron transfer.…”

Section: ••mentioning

confidence: 99%

Oxygen Reduction at Dense Thin-Film Microelectrodes on a Proton-Conducting Electrolyte

Poetzsch

Merkle

Maier

2015

J. Electrochem. Soc.

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The presence of protons in mixed conducting cathode materials contacted with proton conducting electrolytes introduces additional possible mechanistic pathways for the surface oxygen reduction reaction compared to cathodes on oxide ion conducting electrolytes. A reaction network that includes these additional paths with protonated intermediate species is developed. The corresponding rate equations are derived, reflecting the point defects' contributions to the overall oxygen and water partial pressure dependencies. An equivalent circuit is derived for the general case of electrodes that exhibit proton, oxygen ion and electronic conductivity on proton conducting electrolytes. A characteristic circuit element is a chemical capacitance comprising proton and oxygen ion concentration changes. Complications due to nonnegligible electronic transference numbers arising in proton conducting electrolytes at high pO 2 are discussed.

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Section: ••mentioning

confidence: 99%

Oxygen Reduction at Dense Thin-Film Microelectrodes on a Proton-Conducting Electrolyte

Poetzsch

Merkle

Maier

2015

J. Electrochem. Soc.

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“…Hence, while the high temperature gas phase catalysis community understand the term of "oxygen redox reaction" as the formation and the migration of oxygen vacancies, researchers from the field of low temperature electrocatalysis, or from the battery community, would refer this term to the involvement of the O − /O 2− redox couple in an electrochemical reaction. The community of high temperature heterogeneous catalysis, in particular the field of solid oxide fuel cells (SOFC), is well aware of the possibilities given by formation of oxygen vacancies and surface oxygen exchange [8][9][10][11][12]. The physical properties of oxygen vacancies, such as their density, in crystal structure, enthalpy of formation, diffusion kinetics or else playing an important role in catalytic reactions, has been extensively studied and for which the use of high temperature provides the energy to drive their formation and diffusion [8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Factors Controlling the Redox Activity of Oxygen in Perovskites: From Theory to Application for Catalytic Reactions

Yang

Grimaud

2017

Catalysts

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Abstract:Triggering the redox reaction of oxygens has become essential for the development of (electro) catalytic properties of transition metal oxides, especially for perovskite materials that have been envisaged for a variety of applications such as the oxygen evolution or reduction reactions (OER and ORR, respectively), CO or hydrocarbons oxidation, NO reduction and others. While the formation of ligand hole for perovskites is well-known for solid state physicists and/or chemists and has been widely studied for the understanding of important electronic properties such as superconductivity, insulator-metal transitions, magnetoresistance, ferroelectrics, redox properties etc., oxygen electrocatalysis in aqueous media at low temperature barely scratches the surface of the concept of oxygen ions oxidation. In this review, we briefly explain the electronic structure of perovskite materials and go through a few important parameters such as the ionization potential, Madelung potential, and charge transfer energy that govern the oxidation of oxygen ions. We then describe the surface reactivity that can be induced by the redox activity of the oxygen network and the formation of highly reactive surface oxygen species before describing their participation in catalytic reactions and providing mechanistic insights and strategies for designing new (electro) catalysts. Finally, we give a brief overview of the different techniques that can be employed to detect the formation of such transient oxygen species.

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“…As previously mentioned, DFT investigations have been successfully applied to investigate processes determining cathode performance and oxygen vacancy formation and migration in LSM, BSCF and LSCF [70][71][72][73]. Since such investigation has been not yet reported on metal (Pd, Pt, Ag, Cu, Zn, Ni) substituted LSCF, it will be meaningful to carry out such studies on perovskite metal substituted at the B-site.…”

Section: Discussionmentioning

confidence: 99%

“…Another investigation focuses more on the strain caused at the hetero interface leading to increased oxygen vacancy mobility [69]. There is also an idea that the transition state structure of the perovskite may play an important role in the course of the vacancy diffusion [70][71][72][73]. Variations in structural disorder also were pointed out as a factor.…”

Section: A Balance Between Two Effectsmentioning

confidence: 99%

B-Site Metal (Pd, Pt, Ag, Cu, Zn, Ni) Promoted La1−xSrxCo1−yFeyO3–δ Perovskite Oxides as Cathodes for IT-SOFCs

Guo

Puleo

et al. 2015

Catalysts

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Perovskite oxides La1−xSrxCo1−yFeyO3-δ (LSCF) have been extensively investigated and developed as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs) due to mixed ionic-electronic conductivity and high electrooxygen reduction activity for oxygen reduction. Recent literature investigations show that cathode performances can be improved by metal surface modification or B-site substitution on LSCF. Although the specific reaction mechanism needs to be further investigated, the promoting effect of metal species in enhancing oxygen surface exchange and oxygen bulk diffusion is well recognized. To our knowledge, no previous reviews dealing with the effect of metal promotion on the cathodic performances of LSCF materials have been reported. In the present review, recent progresses on metal (Pd, Pt, Ag, Cu, Zn, Ni) promotion of LSCF are discussed focusing on two main aspects, the different synthesis approaches used (infiltration, deposition, solid state reaction, one pot citrate method) and the effects of metal promotion on structural properties, oxygen vacancies content and cathodic performances. The novelty of the work lies in the fact that the metal promotion at the B-site is discussed in detail, pointing at the effects produced by two different approaches, the LSCF surface modification by the metal or the metal ion substitution at the B-site of the perovskite. Moreover, for the first time in a review article, the importance of the combined effects of oxygen dissociation rate and interfacial oxygen transfer rate between the metal phase and the cathode phase is addressed for OPEN ACCESSCatalysts 2015, 5 367 metal-promoted LSCF and compared with the un-promoted oxides. Perspectives on new research directions are shortly given in the conclusion.

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Formation and migration of oxygen vacancies in La_1−xSr_xCo_1−yFe_yO_3−δperovskites: insight from ab initio calculations and comparison with Ba_1−xSr_xCo_1−yFe_yO_3−δ

Cited by 121 publications

References 50 publications

Oxygen Reduction at Dense Thin-Film Microelectrodes on a Proton-Conducting Electrolyte

Oxygen Reduction at Dense Thin-Film Microelectrodes on a Proton-Conducting Electrolyte

Factors Controlling the Redox Activity of Oxygen in Perovskites: From Theory to Application for Catalytic Reactions

B-Site Metal (Pd, Pt, Ag, Cu, Zn, Ni) Promoted La1−xSrxCo1−yFeyO3–δ Perovskite Oxides as Cathodes for IT-SOFCs

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