Crystal structure and surface characteristics of Sr-doped GdBaCo2O6-δ double perovskites: oxygen evolution reaction and conductivity
File(s)
Published version
Supporting information
Author(s)
Type
Journal Article
Abstract
A cheap and direct solution towards engineering better catalysts through identification of novel materials is required for a sustainable energy system. Perovskite oxides have emerged as potential candidates to replace the less economically attractive Pt and IrO2 water splitting catalysts. In this work, excellent electrical conductivity (980 S cm−1) was found for the double perovskite of composition GdBa0.6Sr0.4Co2O6−δ which is consistent with a better oxygen evolution reaction activity with the onset polarisation of 1.51 V with respect to a reversible hydrogen electrode (RHE). GdBa1−xSrxCo2O6−δ with increasing Sr content was found to crystallise in the higher symmetry tetragonal P4/mmm space group in comparison with the undoped GdBaCo2O6−δ which is orthorhombic (Pmmm), and yields higher oxygen uptake, accompanied by higher Co oxidation states. This outstanding electrochemical performance is explained by the wider carrier bandwidth, which is a function of Co–O–Co buckling angles and Co–O bond lengths. Furthermore the higher oxygen evolution activity was observed despite the formation of non-lattice oxides (mainly hydroxide species) and enrichment of alkaline earth ions on the surface.
Date Issued
2017-12-04
Date Acceptance
2017-10-20
Citation
Journal of Materials Chemistry A, 2017, 6, pp.5335-5345
ISSN
2050-7496
Publisher
Royal Society of Chemistry
Start Page
5335
End Page
5345
Journal / Book Title
Journal of Materials Chemistry A
Volume
6
Copyright Statement
© The Royal Society of Chemistry 2018. This is article is licensed under a
Creative Commons Attribution 3.0 Unported Licence (https://creativecommons.org/licenses/by/3.0/0)
Creative Commons Attribution 3.0 Unported Licence (https://creativecommons.org/licenses/by/3.0/0)
Sponsor
Kaust UK Ltd
Engineering & Physical Science Research Council (EPSRC)
Grant Number
N/A
EP/M014142/1
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Physical
Energy & Fuels
Materials Science, Multidisciplinary
Chemistry
Materials Science
ENERGY ION-SCATTERING
NEUTRON POWDER-DIFFRACTION
BOND-VALENCE PARAMETERS
FUEL-CELL CATHODES
OXIDES
ELECTROCATALYSIS
SPECTROSCOPY
REFINEMENT
STABILITY
DIFFUSION
Publication Status
Published