Sc and Nb Dopants in SrCoO3 Modulate Electronic and Vacancy Structures for Improved Water Splitting and SOFC Cathodes

Handle URI:
http://hdl.handle.net/10754/622693
Title:
Sc and Nb Dopants in SrCoO3 Modulate Electronic and Vacancy Structures for Improved Water Splitting and SOFC Cathodes
Authors:
Tahini, Hassan A.; Tan, Xin; Zhou, Wei; Zhu, Zhonghua; Schwingenschlögl, Udo ( 0000-0003-4179-7231 ) ; Smith, Sean C.
Abstract:
SrCoO3 is a promising material in the field of electrocatalysis. Difficulties in synthesising the material in its cubic phase have been overcome by doping it with Sc and Nb ions [Mater. Horiz.2015, 2, 495–501]. Using ab initio calculations and special quasi random structures we undertake a systematic study of these dopants in order to elucidate the effect of doping on electronic structure of the SrCoO3 host and the formation of oxygen vacancies. We find that while the overall electronic structure of SrCoO3 is preserved, increasing the Sc fraction leads to a decrease of electrical conductivity, in agreement with earlier experimental work. For low Sc and Nb doping fractions we find that the oxygen vacancy formation increases relative to undoped SrCoO3. However, as the dopants concentration is increased the vacancy formation energy drops significantly, indicating a strong tendency to accommodate high concentration of oxygen vacancies and hence non-stoichiometry. This is explained based on the electronic instabilities caused by the presence of Sc ions which weakens the B-O interactions as well as the increased degree of electron delocalization on the oxygen sublattice. Sc dopants also shift the p-band centre closer to the Fermi level, which can be associated with experimentally reported improvements in oxygen evolution reactions. These findings provide crucial baseline information for the design of better electrocatalysts for oxygen evolution reactions as well as fuel-cell cathode materials.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Tahini HA, Tan X, Zhou W, Zhu Z, Schwingenschlögl U, et al. (2017) Sc and Nb Dopants in SrCoO3 Modulate Electronic and Vacancy Structures for Improved Water Splitting and SOFC Cathodes. Energy Storage Materials. Available: http://dx.doi.org/10.1016/j.ensm.2017.01.005.
Publisher:
Elsevier BV
Journal:
Energy Storage Materials
Issue Date:
12-Jan-2017
DOI:
10.1016/j.ensm.2017.01.005
Type:
Article
ISSN:
2405-8297
Sponsors:
This research was undertaken with the assistance of UNSW Australia SPF01 funding (SCS). We acknowledge generous allocations of supercomputing time at the Pawsey Supercomputing Centre via the Australian National Computational Merit Allocation Scheme (NCMAS project fr2) and the Energy and Resources Merit Allocation Scheme of the Pawsey Supercomputing Centre (project pawsey0111). Additional computational resources were provided by KAUST on the Shaheen II supercomputer.
Additional Links:
http://www.sciencedirect.com/science/article/pii/S2405829716302264
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorTahini, Hassan A.en
dc.contributor.authorTan, Xinen
dc.contributor.authorZhou, Weien
dc.contributor.authorZhu, Zhonghuaen
dc.contributor.authorSchwingenschlögl, Udoen
dc.contributor.authorSmith, Sean C.en
dc.date.accessioned2017-01-15T13:40:36Z-
dc.date.available2017-01-15T13:40:36Z-
dc.date.issued2017-01-12en
dc.identifier.citationTahini HA, Tan X, Zhou W, Zhu Z, Schwingenschlögl U, et al. (2017) Sc and Nb Dopants in SrCoO3 Modulate Electronic and Vacancy Structures for Improved Water Splitting and SOFC Cathodes. Energy Storage Materials. Available: http://dx.doi.org/10.1016/j.ensm.2017.01.005.en
dc.identifier.issn2405-8297en
dc.identifier.doi10.1016/j.ensm.2017.01.005en
dc.identifier.urihttp://hdl.handle.net/10754/622693-
dc.description.abstractSrCoO3 is a promising material in the field of electrocatalysis. Difficulties in synthesising the material in its cubic phase have been overcome by doping it with Sc and Nb ions [Mater. Horiz.2015, 2, 495–501]. Using ab initio calculations and special quasi random structures we undertake a systematic study of these dopants in order to elucidate the effect of doping on electronic structure of the SrCoO3 host and the formation of oxygen vacancies. We find that while the overall electronic structure of SrCoO3 is preserved, increasing the Sc fraction leads to a decrease of electrical conductivity, in agreement with earlier experimental work. For low Sc and Nb doping fractions we find that the oxygen vacancy formation increases relative to undoped SrCoO3. However, as the dopants concentration is increased the vacancy formation energy drops significantly, indicating a strong tendency to accommodate high concentration of oxygen vacancies and hence non-stoichiometry. This is explained based on the electronic instabilities caused by the presence of Sc ions which weakens the B-O interactions as well as the increased degree of electron delocalization on the oxygen sublattice. Sc dopants also shift the p-band centre closer to the Fermi level, which can be associated with experimentally reported improvements in oxygen evolution reactions. These findings provide crucial baseline information for the design of better electrocatalysts for oxygen evolution reactions as well as fuel-cell cathode materials.en
dc.description.sponsorshipThis research was undertaken with the assistance of UNSW Australia SPF01 funding (SCS). We acknowledge generous allocations of supercomputing time at the Pawsey Supercomputing Centre via the Australian National Computational Merit Allocation Scheme (NCMAS project fr2) and the Energy and Resources Merit Allocation Scheme of the Pawsey Supercomputing Centre (project pawsey0111). Additional computational resources were provided by KAUST on the Shaheen II supercomputer.en
dc.publisherElsevier BVen
dc.relation.urlhttp://www.sciencedirect.com/science/article/pii/S2405829716302264en
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in Energy Storage Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Energy Storage Materials, 12 January 2017. DOI: 10.1016/j.ensm.2017.01.005en
dc.subjectperovskiteen
dc.subjecttransition metalen
dc.subjectelectrocatalysten
dc.subjectSOFCen
dc.subjectDFTen
dc.subjectvacanciesen
dc.titleSc and Nb Dopants in SrCoO3 Modulate Electronic and Vacancy Structures for Improved Water Splitting and SOFC Cathodesen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalEnergy Storage Materialsen
dc.eprint.versionPost-printen
dc.contributor.institutionIntegrated Materials Design Centre (IMDC), School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australiaen
dc.contributor.institutionState Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry & Chemical Engineering, Nanjing Tech University, No. 5 Xin Mofan Road, Nanjing 210009, P.R. Chinaen
dc.contributor.institutionSchool of Chemical Engineering, The University of Queensland, St. Lucia, Queensland 4072, Australiaen
kaust.authorSchwingenschlögl, Udoen
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