Influence of various metallic oxides on the kinetic of the oxygen evolution reaction on platinum electrodes

  • Kambire Ollo
  • Pohan Lemeyonouin Aliou Guillaume Laboratoire de chimie physique-UFR SSMT-Universite Felix Houohouet-Boigny
  • Appia Foffié Thiéry Auguste Laboratoire de chimie physique-UFR SSMT-Universite Felix Houohouet-Boigny
  • Gnamba Corneil Quand-Meme Laboratoire de chimie physique-UFR SSMT-Universite Felix Houohouet-Boigny
  • Kondro Konan Honoré Laboratoire de chimie physique-UFR SSMT-Universite Felix Houohouet-Boigny
  • Lassine Ouattara Laboratoire de chimie physique-UFR SSMT-Universite Felix Houohouet-Boigny
Keywords: platinum, ruthenium dioxide, iridium dioxide, Tafel slope, cyclic voltammetry, electrocatalytic activity, oxygen evolution reaction

Abstract

Pt, 50Pt-50RuO2 and 50Pt-50IrO2 electrodes were prepared on titanium (Ti) substrate by thermal decomposition techniques. The micrographs of 50Pt-50RuO2 and 50Pt-50IrO2 have revealed that their surfaces are rough with cracked structures. That of platinum was smooth, compact and homogeneous. The richer the electrode ‘surface in platinum, thinner is the crack size and also more compact is the electrode’surface. The electrodes have also been characterized electrochemically by cyclic voltammetry in acid (HClO4) and in alkaline (KOH) electrolytes. These characterizations showed that the surface of the 50Pt-50RuO2 and 50Pt-50IrO2 electrodes were composed by platinum and metal dioxide active sites. The Tafel slope obtained on Pt, 50Pt-50RuO2 and 50Pt-50IrO2 for the oxygen evolution reaction (OER) were respectively 120, 90 and 44 mV/dec in acid electrolyte. In the alkaline electrolyte, they were 119, 87 and 42 mV/dec respectively on Pt, 50Pt-50RuO2 and 50Pt-50IrO2 electrodes indicating that for the prepared electrodes, Tafel slopes are the same in acid and in alkaline media. Moreover, in acid and in alkaline media, the kinetic of the oxygen evolution reaction was rapid on 50Pt-50RuO2 and 50Pt-50IrO2 than Pt owing to a synergetic effect of Pt and the oxides. That additional effect of the surface component 50Pt-50RuO2 and 50Pt-50IrO2 electrodes let them possess high electrocatalytic activity towards OER than Pt in the two media. Though the kinetic of the oxygen evolution reaction is practically the same in acidic and alkaline media for all the electrodes, OER occurred at lower overpotential in alkaline electrolyte than in acidic electrolyte on the prepared electrodes.

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Published
26-08-2015
Section
Electrochemical Science