表面改性碳纤维电极的STM微观形貌分析

采用扫描隧道显微镜(STM)技术,分析了经硫酸化学及电化学表面氧化处理前后碳纤维表面的微观形貌变化.处理前碳纤维的微观结构是乱层石墨结构;处理后碳纤维表面的石墨微晶变得清晰规整,同时大大增加了石墨微晶层面边缘碳原子的数目.碳原子间不饱合的C-C键吸附氧而形成含氧官能基团,改善了电极表面的浸润性,提高了电极表面吸附的反应物浓度;同时增加了电化学反应活性中心,因而提高了碳电极的电化学反应活性.电化学处理比化学处理效果更为显著.

Microscopic analysis of surface morphology of modified carbon fiber electrodes by STM

The micromorphology change of carbon fiber surface before and after chemical/ electrochemical treatment with sulf uric acid was studied by using scanning tunneling microscope (STM) technique. Before treatment carbon fibers exhibited the structure of disorder graphite layers,while after treatment graphite microcrystals became more clear and regular on carbon-fiber surface and the amount of carbon atoms at the edge of layer planes of graphite microcrystals was greatly increased. The presence of oxygen-containing functional groups formed by adsorbing oxygen of unsaturated carbon atoms on carbon fiber surfaces improved the wettability of electrode surface as well as enhanced the reactant concentration adsorbed on electrode surface and the active centers of electrochemical reactions,leading to increasing the electrochemical reaction activity of carbon electrodes. Electrochemical treatment effect is preferable to chemical treatment.