Microwave enhanced electrochemistry: mass transport effects and steady state voltammetry in the sub-millisecond time domain
- 作者：Kumar Sur ; Ujjal ; Marken ; Frank ; Rees ; Neil ; Coles ; Barry A. ; Compton ; Richard G. ; Seager ; Robert
- 关键词：Voltammetry ; Microelectrode ; Microwave ; Thermal activation ; Hot spot ; Electrochemical flow cell ; Steady state ; Steam bubble
- 刊名：Journal of Electroanalytical Chemistry
- 出版年：2004
- 期刊代码：27_00220728
- 类别：ph
- 出版时间：November 15, 2004
- 卷：573
- 期：1
- 页码：175-182
- 文件大小：591 K
摘要
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, Formula Not Shown, in aqueous KCl solution. Platinum microelectrodes of 100, 50, and 25 脦脦m diameter are employed and at the 25 脦脦m 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.