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.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors would like to gratefully acknowledge the support of the EPSRC (EP/M014142/1). Additionally, we acknowledge the support of King Abdullah University of Science and Technology, who partially funded this work (S. S. P. and A. C.). We acknowledge the Facility for Analysis, Characterization, Testing and Simulation, Nanyang Technological University, Singapore, for use of their electron microscopy. D. J. P. acknowledges support from the Royal Society for his University Research Fellowship (No. UF100105). D. J. P. and A. R. acknowledge support from the EPSRC (No. EP/M013839/1, EP/M028291/1, EP/M014142/1 and EP/M014304/1). Data supporting this publication is openly available under an ‘Open Data Commons Open Database License’. Additional metadata are available at: http://dx.doi.org/10.17634/154300-55. Please contact Newcastle Research Data Service at http://email@example.com for access instructions.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.