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Mixed Metal-Antimony Oxide Nanocomposites: Low pH Water Oxidation Electrocatalysts with Outstanding Durability at Ambient and Elevated Temperatures

preprint
revised on 21.02.2021, 04:46 and posted on 22.02.2021, 11:16 by Luke Sibimol, Manjunath Chatti, Asha Yadav, Brittany Kerr, Jiban Kangsabanik, Tim Williams, Pavel V. Cherepanov, Akshat Tanksale, Bernt Johannessen, Douglas Macfarlane, Rosalie K. Hocking, Aftab Alam, Aswani Yella, Alexandr Simonov
Proton-exchange membrane water electrolysers provide many advantages for the energy-efficient production of H2, but the current technology relies on high loadings of expensive iridium at the anodes, which are often unstable in operation. To address this, the present work scrutinises the properties of antimony-metal (Co, Mn, Ni, Fe, Ru) oxides synthesised as flat thin films by a solution-based method for the oxygen evolution reaction in 0.5 M H2SO4. Among the non-noble-metal catalysts, only cobalt-antimony and manganese-antimony oxides demonstrate high stability and reasonable activity under ambient conditions, but slowly lose activity at elevated temperatures. The ruthenium-antimony system is highly active, requiring an overpotential of 0.39 ± 0.03 and 0.34 ± 0.01 V to achieve 10 mA cm-2 at 24 ± 2 and 80 °C, respectively, and remaining remarkably stable during one-week tests at 80 °C. The S-number for this catalyst is higher than that for the high-performance benchmark Ir-based systems. Density functional theory analysis and physical characterisation reveal that this high stability is supported by the enhanced hybridisation of the oxygen p- and metal d-orbitals induced by antimony, and can arise from two distinct structural scenarios: either formation of an antimonate phase, or nanoscale intermixing of metal and antimony oxide crystallites.

Funding

Australian Research Council

Australian Renewable Energy Agency

MNRE Government of India

Science and Engineering Research Board, Government of India

IITB-Monash Academy

History

Email Address of Submitting Author

alexandr.simonov@monash.edu

Institution

Monash University

Country

Australia

ORCID For Submitting Author

0000-0003-3063-6539

Declaration of Conflict of Interest

No conflict of interest

Version Notes

Version 1.0

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