Nanocrystalline Graphite for Electrochemical Sensing

Abstract

We report the synthesis and characterization of a new electrode material consisting of nanocrystalline graphite (NCG) deposited onto Pt via microwave plasma chemical vapor deposition. This material exhibits stable and quasi-reversible electrochemistry for a uniquely wide range of model compounds including Fe(CN) 6 4- , Ru(NH 3 ) 6 2+ , and selected catechols and quinones. Raman spectroscopy and electron nanodiffraction were used to confirm the presence of nanocrystals of graphite and support the hypothesis that NCG exhibits electrochemical activity similar to that of edge planes of crystalline graphite. The as-synthesized NCG material did not require any electrochemical pretreatment; however, occasionally, a one-time anodic oxidation did improve the kinetics for the catechol- and quinone-related electron transfer reactions. The electrochemical response of the electrodes was stable even aft er one year of storage time. The electrodes yielded clearly resolvable peaks in the voltammograms for the analytes at concentration levels similar to those in extracellular neural fluids and suggest that the electrode material may be useful for in vivo biological applications. © 2005 The Electrochemical Society. All rights reserved.