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

Naghmehalsadat Mirbagheri, Rui Campos, Elena E. Ferapontova*

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Abstract

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
JournalChemElectroChem
Volume8
Issue9
Pages (from-to)1632-1641
Number of pages10
ISSN2196-0216
DOIs
Publication statusPublished - May 2021

Keywords

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

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