Designing Fe-Based Oxygen Catalysts by Density Functional Theory Calculations

Chen, Chi; Ciucci, Francesco

doi:10.1021/acs.chemmater.6b02953

Cited by 53 publications

(38 citation statements)

References 63 publications

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“…2e . More negative E vf-O value implies easier formation of oxygen vacancies in the reduction environment 35 . The E vf-O value becomes more negative after doping Sr 2+ into Ba 2+ , revealing that the Sr 2+ doping facilitates the formation of oxygen vacancies in the reduction atmosphere.…”

Section: Resultsmentioning

confidence: 99%

Unveiling the key factor for the phase reconstruction and exsolved metallic particle distribution in perovskites

et al. 2021

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To significantly increase the amount of exsolved particles, the complete phase reconstruction from simple perovskite to Ruddlesden-Popper (R-P) perovskite is greatly desirable. However, a comprehensive understanding of key parameters affecting the phase reconstruction to R-P perovskite is still unexplored. Herein, we propose the Gibbs free energy for oxygen vacancy formation in Pr0.5(Ba/Sr)0.5TO3-δ (T = Mn, Fe, Co, and Ni) as the important factor in determining the type of phase reconstruction. Furthermore, using in-situ temperature & environment-controlled X-ray diffraction measurements, we report the phase diagram and optimum ‘x’ range required for the complete phase reconstruction to R-P perovskite in Pr0.5Ba0.5-xSrxFeO3-δ system. Among the Pr0.5Ba0.5-xSrxFeO3-δ, (Pr0.5Ba0.2Sr0.3)2FeO4+δ – Fe metal demonstrates the smallest size of exsolved Fe metal particles when the phase reconstruction occurs under reducing condition. The exsolved nano-Fe metal particles exhibit high particle density and are well-distributed on the perovskite surface, showing great catalytic activity in fuel cell and syngas production.

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Section: Resultsmentioning

confidence: 99%

Unveiling the key factor for the phase reconstruction and exsolved metallic particle distribution in perovskites

et al. 2021

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“…Recent DFT calculations showed that in the case of Fe‐based perovskite (AFeO 3 ), the presence of divalent alkaline‐earth metal cations (i.e., Ca, Sr, and Ba) in A‐site, relative to the lanthanides (in A‐site), substantially lowers the E vac from 3.73 eV to 0.90–1.37 eV . Chen et al surveyed A‐ and B‐site elements that can be incorporated as dopants into BaFeO 3 perovskite framework and studied how the substitution may influence the electronic properties, oxygen vacancy formation, and oxygen migration within these materials . Similar study into Ruddlesden–Popper phases of Ln 2 NiO 4+ δ has also been performed …”

Section: Prediction Of Intrinsic Properties Of Materials By Dft Calcumentioning

confidence: 99%

Recent Progress on Advanced Materials for Solid‐Oxide Fuel Cells Operating Below 500 °C

et al. 2017

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Solid-oxide fuel cells (SOFCs) are electricity generators that can convert the chemical energy in various fuels directly to the electric power with high efficiency. Recent advances in materials and related key components for SOFCs operating at ≈500 °C are summarized here, with a focus on the materials, structures, and techniques development for low-temperature SOFCs, including the analysis of most of the critical parameters affecting the electrochemical performance of the electrolyte, anode, and cathode. New strategies, such as thin-film deposition, exsolution of nanoparticles from perovskites, microwave plasma heating, and finger-like channeled electrodes, are discussed. These recent developments highlight the need for electrodes with higher activity and electrolytes with greater conductivity to generate a high electrochemical performance at lower temperatures.

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“…All lattice constants of Ba 1¹x La x FeO 3¹¤ were less than 4.02 ¡, which is in agreement with the lattice constants evaluated from first principle calculations. 20), 21) The specimen with a nominal composition of BaFe 0.9 -La 0.1 O 3¹¤ was a mixture of cubic and other phases. The lattice constant of the cubic phase, depicted by the closed red reverse triangle in Fig.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Ba1−xLnxFeO3−δ and BaFe1−xLnxO3−δ (Ln: lanthanoid or Y) with cubic perovskite structures and disordered oxide ion vacancies: Effect of ionic radius on substitution site and crystal structure

Yunosuke

Okiba

Reito

et al. 2020

J. Ceram. Soc. Japan

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Various types of samples with nominal compositions of Ba 1¹x Ln x FeO 3¹¤ and BaFe 1¹x Ln x O 3¹¤ (Ln: lanthanoid or Y) were prepared and their phases were analyzed. The types of Ln and their substitutional amounts were clarified to obtain the cubic perovskite phase with a random arrangement of oxide ion vacancies, which have attracted interest as new hole-and oxide-ion-mixed conductors. Ln was classified into three groups based on its ionic radius: Large La was substituted for only the Ba site, whereas small Ln such as Y, Ho, Er, Tm, and Yb were substituted for only the Fe site. Ln with intermediate ionic radii, such as Nd, Sm, Eu, Gd, and Dy, could be substituted for both Ba and Fe sites. Results indicated that the differences in ionic radius between 12-coordinated Ln and Ba as well as between 6-coordinated Ln and Fe were responsible for the determination of substitutional sites. The ratio of the ionic radius of Ln 3+ to that of O 2¹ was also proposed to be a factor in the determination of substitutional sites, which is in agreement with the rigid sphere model. A cubic perovskite phase with a random arrangement of oxide ion vacancies was obtained for Ba 1¹x Ln x FeO 3¹¤ and BaFe 1¹x Ln x O 3¹¤ with a tolerance factor between 0.996 and 1.035 and between 1.008 and 1.035, respectively.

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Designing Fe-Based Oxygen Catalysts by Density Functional Theory Calculations

Abstract: Figure S1. The highest symmetry is used for placing the substitution elements. Images are produced by VESTA 1 .Figure S1. Structure models for A site substitution (a) and B site substitution (b).

Cited by 53 publications

References 63 publications

Unveiling the key factor for the phase reconstruction and exsolved metallic particle distribution in perovskites

Unveiling the key factor for the phase reconstruction and exsolved metallic particle distribution in perovskites

Recent Progress on Advanced Materials for Solid‐Oxide Fuel Cells Operating Below 500 °C

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