Detailed insights into the structural properties and oxygen-pathways in orthorhombic Ba0.5Sr0.5Co0.8Fe0.2O3–δ by electronic-structure theory

Abstract

A number of structural properties of orthorhombic Ba0.5Sr0.5Co0.8Fe0.2O3- (BSCF) have been investigated by means of quantum-chemical calculations based on densityfunctional theory (DFT) and compared with experimental results. The role of the cation arrangements and the location of the oxygen vacancies within the orthorhombic structure have been evaluated and explained by means of bond-analytical techniques.Moreover, a detailed investigation of all oxygen pathways within orthorhombic BSCF

The ionic conductivity of Sm‐doped ceria

“…The higher thermal energy enhances the probability for oxygen vacancies to exit the association radius of the dopant ions (trapping). Furthermore, the probability of jumps around dopants that have a larger migration energy is enhanced (blocking) . Therefore, the maximum of the ionic conductivity is slightly shifted to larger dopant fractions.…”

“…Furthermore, the probability of jumps around dopants that have a larger migration energy is enhanced (blocking). 8,[53][54][55] Therefore, the maximum of the ionic conductivity is slightly shifted to larger dopant fractions. In conclusion, Ce 0.93 Sm 0.07 O 1.965 leads to the largest bulk conductivity for temperatures up to 267°C.…”

Layered Antiferromagnetic Ordering in the Most Active Perovskite Catalysts for the Oxygen Evolution Reaction

“…BSCF : BSCF has an orthorhombic ( Pnma , 62) unit cell with lattice parameters 5.672 Å, 8.024 Å, and 5.649 Å. Ba and Sr occupy different planes and oxygen vacancies mainly accumulate in the Sr plane, leaving about half of the oxygen 4c positions empty . We use the obtained value of U =3.2 eV and 4.0 eV for Co 3+ and Fe 3+ , respectively, from LaCoO 3 and LaFeO 3 .…”

“…BSCF: BSCF has an orthorhombic (Pnma,6 2) unit cell with lattice parameters 5.672 ,8 .024 ,a nd 5.649 .B aa nd Sr occupy different planes and oxygen vacancies mainly accumulate in the Sr plane, leaving about half of the oxygen 4c positions empty. [44] We use the obtained value of U = 3.2 eV and 4.0 eV for Co 3 + and Fe 3 + , respectively,f rom LaCoO 3 and LaFeO 3 .T he reciprocal space was sampled with a( 7 5 7) k-point grid for the optimized lattice parameters: a = 5.413 , b = 7.606 ,a nd c = 5.413 .B SCF shows the typical characteristic of ab ad metal where temperature increases electron transport. The calculated ground state of BSCF agrees with an A-type antiferromagnetic ordering.…”

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

“…processes which are well defined by the differences in the total energies of the equilibrium and the transition states of the materials, where possible GGA inaccuracies are canceled out, rather than in very accurate calculations of ground state energies or predictions of precise magnetic ground states. Indeed, an analysis of the literature [40][41][42][43] evidences that DFT-GGA is a well-established method for such a purpose.…”