抗坏血酸在石墨烯修饰电极的电化学行为研究

Electrochemical behavior of ascorbic acid at graphene modified electrode

以300目鳞片状石墨为原料,采用Hummers法制备氧化石墨并用电化学还原法制备石墨烯修饰电极,分别用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)对石墨,氧化石墨,氧化石墨烯和石墨烯的结构进行了表征。并以石墨烯修饰电极作为电极,用循环伏安法测试了其在含有一定浓度抗坏血酸的磷酸氢二钠-柠檬酸溶液中的电化学行为,选择了测试的最佳条件。在最佳实验条件下,采用计时电量法、OCPT(开路电位)测试抗坏血酸的电化学行为。实验结果表明,抗坏血酸的电化学氧化是单电子的反应,扩散系数D=3.24×10-6cm2·s^(-1),反应速率常数k0=3.78×10-6cm·s^(-1),电荷传递系数β=0.310。

In this paper, 300 mesh flake graphite as raw materials, graphene oxide was prepared by Hummers method and graphene was prepared by electrochemical reduction method and treated as an electrode material. Finally, the graphite powder, graphite oxide, graphene oxide and graphene were analyzed by X-ray diffraction（XRD）and FTIR spectra. Electrochemical behavior of graphene modified electrode was characterized by Cyclic Voltamme-try in disodium hydrogen phosphate-citric acid solution containing a certain concentration of ascorbic acid. We se-lected the optimal test conditions. After selecting the optimal experimental conditions, we use chronograph coulom-etry and OCPT to measure electrochemical behavior of ascorbic acid. Experimental results show that the oxidation of ascorbic acid is the reaction of one electron, diffusion coefficient D is 3.24×10^-6 cm^2·s^-1, reaction rate constant k0 is 5×10^-5 cm^2·s^-1, and charge-transfer coefficient β is 0.310.