Comparative Study of Electrochemical Performances of Three Carbon-Based Electrode Materials

The electrochemical properties of three carbon-based electrodes including boron-doped nanocrystalline diamond (BDND), boron-doped microcrystalline diamond (BDMD), and glassy carbon (GC) were compared. We used scanning electron microscopy to characterize the two diamond electrodes and the grain sizes of the BDMD and BDND films were 1-5 mu m and 20-100 nm, respectively. The phase composition was characterized by Raman spectroscopy and high-quality BDMD and BDND films were formed by hot-filament chemical vapor deposition. Cyclic votammograms for 0.5 mol.L-1 H2SO4 showed that the potential windows for the BDND and BDMD electrodes were 3.3 and 3.0 V, respectively. The potential windows were much wider than that of the GC electrode (2.5 V). The cyclic voltammograms and Nyquist plots of the impedance measurements for [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) show peak to peak separations (Delta E-p) of 73, 92, and 112 mV and electron transfer resistances (R-et) of (98 +/- 5), (260 +/- 19), and (400 +/- 25) Omega for the BDND, BDMD, and GC electrodes, respectively. We also investigated the oxidation of 0.1 mmol.L-1 bisphenol A (BPA) on the three carbon-based electrodes. The above-mentioned electrochemical results reveal that the two diamond electrodes have wider potential windows, better reversibility, faster electron transfer, and higher stability than the GC electrode. Additionally, the BDND electrode shows better electrochemical properties than the BDMD electrode.