[Electrocatalytic behavior of diamond electrode for organic pollutant]

The physical and electrochemical behaviors of the boron-doped diamond film electrode prepared by chemical vapor deposition technique were studied. The surface microstructure of the electrode was demonstrated by means of scanning electron microscopy. The electrochemical behaviors of the electrode were investigated using cyclic voltammetry and AC Impedance. The diamond films were polycrystalline and had uniform grains in micron grade. The results showed that the electrode had a very wide potential window and very low background current. The potential windows in acidic, neutral or alkaline medium were separately 4.3 V, 4.0 V and 3.0 V. The background current was as low as -9 x 10(-6)-5 x 10(-7) A. In electrolyte including Ferri/Ferrocyanide, the electrode surface kept good activity, and the electrochemical reaction carrying out on the surface was a diffusion-controlled reaction, with good quasi-reversibility. Studies of the oxidation of organic compounds showed that the electrocatalytic oxidation behavior was selective. Compared with Pt and graphite electrodes, the diamond electrode could oxidate aromatic compounds like phenol and nitrobenzene effectively, and the process of oxidation was very simple and complete.