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Data for Exploiting the flexibility of the pyrochlore composition for acid-resilient Iridium oxide electrocatalysts in proton exchange membranes
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Walton, Richard I., Burnett, David L., Petrucco, Enrico, Kashtiban, Reza J., Parker, Stewart F. and Sharman, Jonathan F. (2021) Data for Exploiting the flexibility of the pyrochlore composition for acid-resilient Iridium oxide electrocatalysts in proton exchange membranes. [Dataset]
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Official URL: http://wrap.warwick.ac.uk/159832/
Abstract
Iridate pyrochlore oxides (Na,Ca)2-x(Ir2-yMy)O6·nH2O (M = Sb, Zr, Ru, Rh) are studied as electrocatalysts for the oxygen evolution reaction under acid conditions. The materials crystallise from aqueous solution under alkali hydrothermal conditions with 10-40 nm crystallite size. Refinement of their crystal structures using both powder neutron and X-ray diffraction determined the composition of the materials, and Ir LIII-edge XANES spectroscopy shows the average Ir oxidation state to be close to 4.5 in all materials, consistent with bond valence sums. All materials show high electrocatalytic activity for the oxygen evolution reaction and the electrocatalyst which best maintains activity on cycling is the sodium-free Ca2-xIr2O6·nH2O, while the (Na,Ca)2-xIr2O6·nH2O material shows highest activity when normalised for surface area. In membrane electrode assemblies, carbon corrosion is minimised, making the materials suitable for use in catalyst layers in proton exchange membrane devices, such as electrolysers and fuel cells. Under strongly acidic conditions it is proved that while A-site Ca and Na are readily leached, the average pyrochlore structure is maintained, as is electrocatalytic activity, with charge balance achieved by inclusion of protons in the pyrochlore structure in the form of bridging hydroxyls, as seen using inelastic neutron scattering spectroscopy.
Item Type: | Dataset | |||||||||||||||||||||
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Subjects: | Q Science > QC Physics Q Science > QD Chemistry T Technology > TK Electrical engineering. Electronics Nuclear engineering |
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Divisions: | Faculty of Science, Engineering and Medicine > Science > Chemistry | |||||||||||||||||||||
Type of Data: | ascii data supporting published article | |||||||||||||||||||||
Library of Congress Subject Headings (LCSH): | Iridium oxide, Electrocatalysis, Proton exchange membrane fuel cells, Platinum group catalysts, Neutrons -- Diffraction | |||||||||||||||||||||
Publisher: | University of Warwick, Department of Chemistry | |||||||||||||||||||||
Official Date: | 2 November 2021 | |||||||||||||||||||||
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Status: | Not Peer Reviewed | |||||||||||||||||||||
Publication Status: | Published | |||||||||||||||||||||
Media of Output (format): | ASCII | |||||||||||||||||||||
Access rights to Published version: | Open Access (Creative Commons) | |||||||||||||||||||||
Copyright Holders: | University of Warwick | |||||||||||||||||||||
Description: | All data files are 2-column ascii format, labelled according to the figures in the main text. Consult the figures for the column labels. |
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Date of first compliant deposit: | 2 November 2021 | |||||||||||||||||||||
Date of first compliant Open Access: | 2 November 2021 | |||||||||||||||||||||
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