Effects of Carbon Ion on Glassy Carbon Electrode as Chemical Sensor
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Effects of Carbon Ion on Glassy Carbon Electrode as Chemical Sensor B. Chhay, L. Bowman, D. Ila Center for Irradiation of Materials, Alabama A&M University, Normal, AL 35762, U.S.A.
ABSTRACT Glassy polymeric carbon (GPC) is a material commonly used for making electrodes for cyclic voltammetric (CV) and amperometric measurements. Previous work done at Alabama A&M University (AAMU) has shown that high energy ion beams can be used to improve the physical properties of GPC in general. In this work, we fabricated a glassy polymeric carbon electrode and we used carbon ions to activate it. Surface analyses including Raman spectroscopy, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were performed to compare the changes in surface morphology and structure before and after carbon ion bombardment.
INTRODUCTION Glassy carbon electrodes (GCE) have received enormous attention in the last years due to their unique structural and chemical properties [1 - 5]. The importance of surface chemistry to the electrochemical behavior of carbon electrode has been extensively studied. Various wellestablished and novel surface modification procedures were used on glassy carbon electrodes to yield surfaces with low oxide content. In order to fully exploit GCE detection capability, a relationship between the surface science and the electrochemical properties must be understood. Typically, electrode polishing is used to increase activation of the carbon. Ion implantation is a technique that can be used to activate, roughen and increase electric conductivity of the electrode [6, 7]. In this work, we activated the electrode by combining polishing and ion bombardment.
EXPERIMENT The glassy polymeric carbon electrode fabricated at Alabama A&M University was prepared from a precursor phenolic resin obtained from Georgia Pacific. The resin was poured in a tubemold with one closed end and placed in an oven at 70°C to cure. Once the resin solidified, we demolded the cured resin, cut its length to a desired dimension and further heat treated it to 1000°C in argon. At the end of the pyrolysis we obtained a rod of GPC with a diameter and length of 5.4 mm and 6.1 mm, respectively. Using a raster scanned beam of carbon ions with 650 keV energy from the Pelletron ion accelerator, we performed a homogeneous bombardment on the GCE surface at room temperature and to a fluence of 1×1014 ions/cm2. The incident 650 keV was chosen such that
carbon ions would stop at about 1.44 μm below the surface [8], where they would not interact with the surface analysis measurements. The electrode was then assembled by pressing a copper rod against the GPC rod. Cyclic voltammetry (CV) experiments were performed with a conventional three-electrode cell. The electrochemical experiments were carried out with a BAS CV-50W potentiostat connected to a personal computer controlling the experiments and data acquisition. Two glassy carbon electrodes were compared as working electrodes. The first one was a commercial GCE provided by BAS, and th
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