碳纳米管的快速功能化及电催化

将耐尔兰(Nile Blue, NB)分子修饰到碳纳米管(CNT)表面形成NB-CNT纳米复合体, 谱学结果表明, NB不仅能快速、高效地修饰到CNT表面, 而且还能有效地改善CNT在水溶液中的分散性能. 将NB-CNT修饰到玻碳(GC)电极表面制备了NB-CNT/GC电极, 循环伏安结果显示, 其伏安曲线上不仅表现出一对良好的、几乎对称的NB单体的氧化还原峰, 式量电位E⁰'几乎不随扫速而变化其平均值为(－0.422±0.002) V (vs. SCE, 0.1 mol/L PBS, pH 7.0)]; 而且还显示出NB聚合体分子的氧化还原峰, E⁰'为－0.191 V (100 mV/s时). 进一步的实验结果表明, NB和CNT对NADH(即还原型β-烟酰胺腺嘌呤二核苷酸, 又称还原型辅酶I)的电化学氧化具有协同催化作用, 能使其氧化过电位降低多于560 mV; NB-CNT/GC电极还能较好地响应脱氢酶催化底物氧化过程中体系内NADH浓度的变化. 本文对碳纳米管功能化方法具有简单快速、电极制作容易以及催化效率高等优点, NB-CNT/GC电极有望在制作脱氢酶传感器方面得到应用.

Rapid Functionalization of Carbon Nanotube and Its Electrocatalysis

It was reported that carbon nanotube (CNT) was functionalized with the electroactive Nile Blue (NB), which was a phenoxazine dye, by a method of adsorption to form an NB-CNT nanocomposite. The spectroscopic results showed that NB can be rapidly and effectively adsorbed on the surface of CNT with high stability without changing the native structure of NB and the structure properties of CNT. Moreover, it was shown that the dispersion ability of CNT in aqueous solution had a significant improvement after CNT was functionalized with NB even at a level of high concentration, for example 5 mg of NB-CNT per 1 mL of H₂O. The NB-CNT/GC electrode was fabricated by modifying NB-CNT nanocomposite on the GC electrode surface and its electrochemical properties were investigated by cyclic voltammetry. The cyclic voltammetric results indicated that CNT could improve the electrochemical behavior of NB and greatly enhance its redox peak currents. While the NB-CNT/GC electrode exhibited a pair of well-defined and nearly symmetrical redox peaks with the formal potential of (－0.422±0.002) V (vs. SCE, 0.1 mol/L PBS, pH 7.0), which was almost independent of the scan rates, for electrochemical reaction of NB monomer, the redox peak potential of NB polymer located at about －0.191 V. The experimental results also demonstrated that NB and CNT could synergistically catalyze the electrochemical oxidation of NADH (β-nicotinamide adenine dinucleotide, reduced form) and NB-CNT exhibited a high performance with lowering the overpotential by more than 560 mV. The NB-CNT/GC electrode could effectively sense the concentration of NADH, which was produced during the process of oxidation of substrate (for example ethanol) catalyzed by dehydrogenase (for example alcohol dehydrogenase). The presented method for functionalization of CNT had several advantages, such as rapid and facile CNT functionalization, easy electrode fabrication, high electrocatalytic activity, etc., and could be used for fabrication of electrochemical biosensor based on dehydrogenase.