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Electrocatalytic Oxidation of Water by OH- and H2O-Capped IrOx Nanoparticles Electrophoretically Deposited on Graphite and Basal Plane HOPG: Effect of the Substrate Electrode**

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  • Naghmehalsadat Mirbagheri, University of Freiburg
  • ,
  • Rui Campos, University of Antwerp
  • ,
  • Elena E. Ferapontova

Iridium oxide (IrOx) is one of the most efficient electrocatalysts for water oxidation reaction (WOR). Here, WOR electrocatalysis by 1.6 nm IrOx nanoparticles (NPs) electrophoretically deposited onto spectroscopic graphite (Gr) and basal plane highly ordered pyrolytic graphite (HOPG) was studied as a function of NPs’ capping ligands and electrodeposition substrate. On Gr, OH- and H2O-capped NPs exhibited close sub-monolayer surface coverages and specific electrocatalytic activity of 18.9-23.5 mA nmol−1 of IrIV/V sites, at 1 V and pH 7. On HOPG, OH-capped NPs produced films with a diminished WOR activity of 5.17±2.40 mA nmol−1. Electro-wettability-induced changes impeded electrophoretic deposition of H2O-capped NPs on HOPG, WOR currents being 25-fold lower than observed for OH-capped ones. The electrocatalysis efficiency correlated with hydrophilic properties of the substrate electrodes, affecting morphological and as a result catalytic properties of the formed IrOx films. These results, important both for studied and related carbon nanomaterials systems, allow fine-tuning of electrocatalysis by a proper choice of the substrate electrode.

Original languageEnglish
Pages (from-to)1632-1641
Number of pages10
Publication statusPublished - May 2021

Bibliographical note

Publisher Copyright:
© 2021 Wiley-VCH GmbH

    Research areas

  • basal plane highly ordered pyrolytic graphite (HOPG), electrocatalysis, graphite, iridium oxide nanoparticles, water oxidation reaction

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