金刚石膜电极对有机污染物的电催化特性

研究了化学气相沉积法(CVD)制备得到的掺硼金刚石膜电极的物理性质和电化学性能.用扫描电子显微镜(SEM)法表征了金刚石膜的表面微观结构,采用循环伏安法和交流阻抗法研究了电极的电化学性质.结果表明,金刚石薄膜表面形态为复晶结构,颗粒大小均匀,掺硼后使电极具有良好的导电性能.金刚石膜电极具有很宽的电势窗口,在酸性、中性和碱性3种介质中分别为4.3V、4.0V和3.0V.同时,金刚石膜电极的背景电流非常低,为-9×10^-6～5×10^-7A.在铁氰化钾电解液中,金刚石膜电极表面在反应过程中始终保持良好的活性,在表面进行的电化学反应具有良好的准可逆性,其电极动力学主要是受扩散过程所控制.金刚石膜电极对有机污染物的催化氧化作用具有选择性.与铂电极和石墨电极相比,金刚石膜电极对苯酚、硝基苯等芳香化合物的催化氧化强烈,氧化过程较为简单、彻底.这些性质表明金刚石膜电极是一种非常适用于环保处理的新型电极.

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.