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Catalysis of water oxidation in acetonitrile by iridium oxide nanoparticles.
Journal article

Catalysis of water oxidation in acetonitrile by iridium oxide nanoparticles.

  • Hidalgo-Acosta JC Laboratoire d'Electrochimie Physique et Analytique , Ecole Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland . Email: Hubert.Girault@epfl.ch.
  • Méndez MA Laboratoire d'Electrochimie Physique et Analytique , Ecole Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland . Email: Hubert.Girault@epfl.ch.
  • Scanlon MD Laboratoire d'Electrochimie Physique et Analytique , Ecole Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland . Email: Hubert.Girault@epfl.ch.
  • Vrubel H Laboratoire d'Electrochimie Physique et Analytique , Ecole Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland . Email: Hubert.Girault@epfl.ch.
  • Amstutz V Laboratoire d'Electrochimie Physique et Analytique , Ecole Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland . Email: Hubert.Girault@epfl.ch.
  • Adamiak W Institute of Physical Chemistry , Polish Academy of Sciences , Kasprazaka 44/52 , 01-224 Warsaw , Poland . Email: mopallo@ichf.edu.pl.
  • Opallo M Institute of Physical Chemistry , Polish Academy of Sciences , Kasprazaka 44/52 , 01-224 Warsaw , Poland . Email: mopallo@ichf.edu.pl.
  • Girault HH Laboratoire d'Electrochimie Physique et Analytique , Ecole Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland . Email: Hubert.Girault@epfl.ch.
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  • 2017-11-23
Published in:
  • Chemical science. - 2015
English Water oxidation catalysed by iridium oxide nanoparticles (IrO2 NPs) in water-acetonitrile mixtures using [RuIII(bpy)3]3+ as oxidant was studied as a function of the water content, the acidity of the reaction media and the catalyst concentration. It was observed that under acidic conditions (HClO4) and at high water contents (80% (v/v)) the reaction is slow, but its rate increases as the water content decreases, reaching a maximum at approximately equimolar proportions (≈25% H2O (v/v)). The results can be rationalized based on the structure of water in water-acetonitrile mixtures. At high water fractions, water is present in highly hydrogen-bonded arrangements and is less reactive. As the water content decreases, water clustering gives rise to the formation of water-rich micro-domains, and the number of bonded water molecules decreases monotonically. The results presented herein indicate that non-bonded water present in the water micro-domains is considerably more reactive towards oxygen production. Finally, long term electrolysis of water-acetonitrile mixtures containing [RuII(bpy)3]2+ and IrO2 NPs in solution show that the amount of oxygen produced is constant with time demonstrating that the redox mediator is stable under these experimental conditions.
Language
  • English
Open access status
gold
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Persistent URL
https://sonar.rero.ch/global/documents/156182
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