Microwave enhanced electrochemistry: Mass transport effects and steady state voltammetry in the sub-millisecond time domain

Ujjal Kumar Sur, Frank Marken, Neil Rees, Barry A. Coles, Richard G. Compton, Robert Seager

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)

Abstract

In situ microwave activation of electrochemical processes is possible by self-focusing of intense microwave radiation into a region close to the electrode|solution (electrolyte) interface of a microelectrode placed inside a microwave cavity. A systematic study of the microwave activation effects in electrochemical processes is reported for two redox systems, Fe(CN) 6 3-/4- and Ru(NH3)6 3+/2+, in aqueous KCl solution. Platinum microelectrodes of 100, 50, and 25 μm diameter are employed and at the 25 μm diameter electrode, extreme current enhancements of up to three orders of magnitude are detected. A typical Nernst diffusion layer thickness in aqueous solution of less than 100 nm can be achieved routinely and, consequently, high temperature steady state voltammetry is possible in the sub-millisecond time domain. Volatile reagents reduce the efficiency of this effect and therefore a steam bubble mechanism is proposed to explain the observations. Microwave effects on the rate of interfacial electron transfer are discussed.

Original languageEnglish
Pages (from-to)175-182
Number of pages8
JournalJournal of Electroanalytical Chemistry
Volume573
Issue number1
DOIs
Publication statusPublished - 15 Nov 2004

Keywords

  • Electrochemical flow cell
  • Hot spot
  • Microelectrode
  • Microwave
  • Steady state
  • Steam bubble
  • Thermal activation
  • Voltammetry

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Electrochemistry

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