Electrochemical impedance of H2-evolving Pt electrode under bubble-induced and forced convections in alkaline solutions

C. Gabrielli, F. Huet, R. P. Nogueira

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

The aim of this paper is to investigate the combined influence of H2 bubble evolution and forced convection on the impedance of Pt in NaOH and NaOH+K3[Fe(CN)6] solutions. Results have shown that bubble evolution did not disturb measurements so that the impedance technique was appropriate for investigating gas-evolving electrodes. At strong bubble evolution, the overall process was qualitatively the same in both electrolytes, without mass-transport limitations, regardless the presence of ferricyanide. However, mass-transport controlled processes appeared in some conditions, depending on the electrode rotation speed and current density, which had opposite effects on bubble evolution. In these intermediate conditions in which bubble evolution was not strong enough to continuously renew the diffusion layer, but enhanced mass transfer, two new loops appeared in the Nyquist impedance diagram. The interface was modeled by considering that ferricyanide reduction occurred on Pt active sites not blocked by adsorbed hydrogen or bubbles. Simulated and experimental curves were in good agreement.

Original languageBritish English
Pages (from-to)2043-2048
Number of pages6
JournalElectrochimica Acta
Volume47
Issue number13-14
DOIs
StatePublished - 25 May 2002

Keywords

  • Bubble evolution
  • Bubble-induced convection
  • EIS
  • Forced convection
  • Modelling
  • Redox couple

Fingerprint

Dive into the research topics of 'Electrochemical impedance of H2-evolving Pt electrode under bubble-induced and forced convections in alkaline solutions'. Together they form a unique fingerprint.

Cite this