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Ir–Re binary alloys under extreme conditions and their electrocatalytic activity in methanol oxidation

Kirill Yusenko, Elena Bykova, Maxim Bykov, Sephira Riva, Wilson A. Crichton, Maria V. Yusenko, Aleksandr S. Sukhikh, Serena Arnaboldi, Michael Hanfland, Leonid S. Dubrovinsky, Sergey A. Gromilov

Acta Materialia, Volume: 139, Pages: 236 - 243

Swansea University Author: Kirill Yusenko

Abstract

The formation of the hcp-Ir0.70Re0.30 alloy from the single-source precursor (NH4)2[Ir0.70Re0.30Cl6] upon heating in hydrogen atmosphere can be associated with the formation of two intermediates: a crystalline iridium-based intermediate and a fcc-structured alloy. Ir–Re alloys show lower thermal exp...

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Published in: Acta Materialia
ISSN: 1359-6454
Published: 2017
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa34955
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Abstract: The formation of the hcp-Ir0.70Re0.30 alloy from the single-source precursor (NH4)2[Ir0.70Re0.30Cl6] upon heating in hydrogen atmosphere can be associated with the formation of two intermediates: a crystalline iridium-based intermediate and a fcc-structured alloy. Ir–Re alloys show lower thermal expansion coefficients and smaller compressibility in comparison with individual metals. The high-temperature high-pressure treatment of hcp-Ir0.70Re0.30 alloy enable us to probe the Ir–Re pressure dependent phase diagram. The miscibility gap between hcp and fcc alloys slightly shifts towards the rhenium side below 4 GPa. Above 4 GPa, the miscibility gap does not drift with pressure and narrows with compression. The electrocatalytic activity of Ir–Re alloys has been tested for methanol oxidation in acidic water solution. Ir–Re alloys show higher electrocatalytic activity in comparison with pure Ir and Re, which makes them perspective candidates for fuel cells application. The highest electrocatalytic activity has been obtained for the two-phase Ir0.85Re0.15 composition.
Keywords: High-pressure; High-temperature; Alloys; Phase diagrams; X-ray diffraction; Electrocatalysis
College: Faculty of Science and Engineering
Start Page: 236
End Page: 243