All-Diamond Microelectrodes as Solid State Probes for Localized Electrochemical Sensing
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- 作者：Eduardo L. Silva ; Cristol P. Gouv锚a ; Marcela C. Quevedo ; Miguel A. Neto ; Braulio S. Archanjo ; Ant贸nio J. S. Fernandes ; Carlos A. Achete ; Rui F. Silva ; Mikhail L. Zheludkevich ; Filipe J. Oliveira
- 刊名：Analytical Chemistry
- 出版年：2015
- 出版时间：July 7, 2015
- 年：2015
- 卷：87
- 期：13
- 页码：6487-6492
- 全文大小：343K
- ISSN：1520-6882
文摘
The fabrication of an all-diamond microprobe is demonstrated for the first time. This ME (microelectrode) assembly consists of an inner boron doped diamond (BDD) layer and an outer undoped diamond layer. Both layers were grown on a sharp tungsten tip by chemical vapor deposition (CVD) in a stepwise manner within a single deposition run. BDD is a material with proven potential as an electrochemical sensor. Undoped CVD diamond is an insulating material with superior chemical stability in comparison to conventional insulators. Focused ion beam (FIB) cutting of the apex of the ME was used to expose an electroactive BDD disk. By cyclic voltammetry, the redox reaction of ferrocenemethanol was shown to take place at the BDD microdisk surface. In order to ensure that the outer layer was nonelectrically conductive, a diffusion barrier for boron atoms was established seeking the formation of boron鈥揾ydrogen complexes at the interface between the doped and the undoped diamond layers. The applicability of the microelectrodes in localized corrosion was demonstrated by scanning amperometric measurements of oxygen distribution above an Al鈥揅u鈥揅FRP (Carbon Fiber Reinforced Polymer) galvanic corrosion cell.