Oxygen Vacancy Formation Characteristics in the Bulk and Across Different Surface Terminations of La_(1−x)Sr_xFe_(1−y)Co_yO_(3−δ) Perovskite Oxides for CO₂ Conversion

Authors

Debtanu Maiti, University of South Florida
Yolanda A. Daza, University of South Florida
Matthew M. Yung, National Renewable Energy Laboratory
John N. Kuhn, University of South FloridaFollow
Venkat R. Bhethanabotla, University of South FloridaFollow

Document Type

Article

Publication Date

2016

Digital Object Identifier (DOI)

https://doi.org/10.1039/C5TA10284G

Abstract

Density functional theory (DFT) based investigation of two parameters of prime interest – oxygen vacancy and surface terminations along (100) and (110) planes – has been conducted for La_(1−x)Sr_xFe_(1−y)Co_yO_(3−δ) perovskite oxides in view of their application towards thermochemical carbon dioxide conversion reactions. The bulk oxygen vacancy formation energies for these mixed perovskite oxides are found to increase with increasing lanthanum and iron contents in the ‘A’ site and ‘B’ site, respectively. Surface terminations along (100) and (110) crystal planes are studied to probe their stability and their capabilities to accommodate surface oxygen vacancies. Amongst the various terminations, the oxygen-rich (110) surface and strontium-rich (100) surface are the most stable, while transition metal-rich terminations along (100) revealed preference towards the production of oxygen vacancies. The carbon dioxide adsorption strength, a key descriptor for CO2 conversion reactions, is found to increase on oxygen vacant surfaces thus establishing the importance of oxygen vacancies in CO₂ conversion reactions. Amongst all the surface terminations, the lanthanum-oxygen terminated surface exhibited the strongest CO₂ adsorption strength. The theoretical prediction of the oxygen vacancy trends and the stability of the samples were corroborated by the temperature-programmed reduction and oxidation reactions and in situ XRD crystallography.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Journal of Materials Chemistry A, v. 4, p. 5137-5148

Scholar Commons Citation

Maiti, Debtanu; Daza, Yolanda A.; Yung, Matthew M.; Kuhn, John N.; and Bhethanabotla, Venkat R., "Oxygen Vacancy Formation Characteristics in the Bulk and Across Different Surface Terminations of La_(1−x)Sr_xFe_(1−y)Co_yO_(3−δ) Perovskite Oxides for CO₂ Conversion" (2016). Chemical, Biological and Materials Engineering Faculty Publications. 34.
https://digitalcommons.usf.edu/ech_facpub/34