title: Catalytic Dynamics and Oxygen Diffusion in Doped PrBaCo2O(5.5+δ) Thin Films.
abstract: The Sr and Fe codoped double perovskites PrBaCo2O5.5+δ (PrBCO) thin films of Pr(Ba0.5Sr0.5)(Co1.5Fe0.5)O5.5+δ (PBSCFO) were epitaxially grown for chemical catalytic studies. The resistance behavior of PBSCFO epitaxial films was monitored under the switching flow of reducing and oxidizing gases as a function of the gas flow time, t, using an electrical conductivity relaxation (ECR) experimental setup. The R(t) vs t relationships determined at various temperatures show the occurrence of two oxidation processes, Co(2+)/Co(3+) ↔ Co(3+) and Co(3+) ↔ Co(3+)/Co(4+). Mathematical fitting of the observed R(t) vs t relationships was carried out using Fick's second law for one-dimensional diffusion of charge carriers to derive the diffusivity D(T) and τ(T) for the two processes at various temperatures, T. The D(T) vs T relationships were analyzed in terms of the Arrhenius relationship to find the activation energies Ea for each process. Oscillations in the dR(t)/dt plots, observed under oxidation reactions, were discussed in terms of a layer-by-layer oxygen vacancy exchange diffusion mechanism. Our work suggests that thin films of LnBCO (Ln = lanthanide) with their A and B sites doped as in PBSCFO are excellent candidates for the development of low or intermediate temperature energy conversion devices and gas sensor applications.
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States.|Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.|Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Erik
authors.initials: E
authors.lastname: Enriquez
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States.|Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.|Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Xing
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States.|Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.|Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Shanyong
authors.initials: S
authors.lastname: Bao
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States.|Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.|Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Zach
authors.initials: Z
authors.lastname: Harrell
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States.|Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.|Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Chonglin
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States.|Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.|Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Sihyuk
authors.initials: S
authors.lastname: Choi
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States.|Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.|Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Areum
authors.initials: A
authors.lastname: Jun
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States.|Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.|Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Guntae
authors.initials: G
authors.lastname: Kim
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States.|Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.|Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Myung-Hwan
authors.initials: MH
authors.lastname: Whangbo
keywords: MIEC; PrBaCo2O5+δ; ion diffusion; surface catalysis; transport properties