碳纳米管/聚苯胺化学修饰电极的制备及其对抗坏血酸的检测

Carbon Nanotubes/Polyaniline Chemically Modified Electrode:Preparation and Ascorbic Acid Detection

通过恒电压沉积法将纳米金属镍沉积于石墨电极表面,经化学气相沉积法在石墨电极表面原位生长出碳纳米管(CNTs),通过电化学聚合法在CNTs表面原位聚合聚苯胺,从而获得化学修饰电极。采用扫描电子显微镜对所得电极形貌结构进行表征,并研究CNTs与PNAI复合电极对抗坏血酸(AA)的检测效果。研究结果表明:制备的CNTs都能均匀地生长在石墨电极表面,纳米中空管状结构都保持完好;PANI均匀地包覆在CNTs管壁上,复合材料呈现出典型的三维网状结构。所制备的CNTs/PANI修饰电极对AA具有良好的电化学响应,其中管径较小CNTs的修饰电极对AA的电化学响应更强:具有更宽的检测范围和更低的检出限。其检测线性范围为1.0×10^(-6)~4.5×10^(-4) mol/L,检出限为1.0×10^(-7) mol/L(S/N=3)。且具有良好的稳定性、重复性和可靠性。

Nickel catalyst was deposited on a graphite electrode （GE） surface by constant voltage deposition method. With the nickel catalyst, carbon nanotubes （CNTs） were grown in situ on the GE surface to prepare CNTs chemically modified electrode （GSCNTs-CME） by catalytic chemical vapor deposition. After that, polyaniline （PANI） was polymerized in situ on the GSCNTs-CME to obtain GSCNTs/PANI-CME by electrochemical polymerization. Morphology and structure of the obtained electrodes were characterized by scanning electron microscope. Detection performances of the GSCNTs/PANI-CME on ascorbic acid （AA） were evaluated on an electrochemical workstation. Results show that the CNTs grow uniformly on the GE surface and the original tubular structure is remained well. PANI is coated uniformly on the surface of CNTs in the obtained composite with a typical three-dimensional network structure. The GSCNTs/PANI-CMEs show excellent electrochemical response to AA, amongst which the GSCNTs/PANI-CME with small-diameter CNTs shows stronger electrochemical response （wider linear detection range and lower detection limit） to AA. And its linear detection range and detection limit are 1.0×10-6~4.5×10-4 mol/L and 1.0×10-7 mol/L （S/N = 3）, respectively. Therefore, the GSCNTs/PANI-CME shows excellent stability, repeatability and reliability.