Acta Chimica Sinica ›› 2013, Vol. 71 ›› Issue (02): 239-245.

Article

三维金纳米团簇/多壁碳纳米管-Nafion膜修饰电极的电化学制备及血红蛋白的直接电化学

1. a 中国海洋大学环境科学与工程学院 青岛 266100;
b 北京师范大学化学学院 北京 100875
• 投稿日期:2012-11-06 发布日期:2013-01-09
• 通讯作者: 赵越 E-mail:yuezhao@ouc.edu.cn
• 基金资助:

国家自然基金(No. 41201569/D011102)和中央高校基本科研业务费实验室研究基金项目(No. 201251007).

Electrodeposition of Gold Nanoparticle Clusters on Multi-Wall Carbon Nanotubes and the Direct Electrochemistry of Hemoglobin

Zhao Yuea, Hong Boa, Fan Louzhenb

1. a College of Environmental Science and Technology, Ocean University of China, Qingdao 266100;
b College of Chemistry, Beijing Normal University, Beijing 100875
• Received:2012-11-06 Published:2013-01-09
• Supported by:

Project supported by the National Natural Science Foundation of China (No. 41201569/D011102) and the Fundamental Research Funds for the Central Universities (No. 201251007).

Three-dimensional structure gold nanoparticle clusters (3D Au) were electrodeposited onto multiwalled carbon nanotubes (MWCNTs) through improved three-step method, which involves: (1) potential cycling (CV, 200 mV·s-1) from +1.8 to -0.4 V was performed in 0.5 mol/L K2SO4 solutions for 10 min in order to produce oxide functional groups (carbonyl, hydroxyl, and carboxyl) at the defect sites located at the ends and/or the sidewalls of MWCNTs, (2) electrochemical oxidation of the Au(III) complex to the Au(V) complex from 2 mol/L K2PtCl4+0.1 mol/L K2SO4 aqueous solutions by using potential-step method (PS). The potential was jumped from 0.3 V to 1.1 V with different pulse width and this was repeated until a steady pulse current was reached. and (3) electrochemical transformation of the Au(V) complex to Au nanoparticle clusters on the surface of MWCNTs through cycling from +1.0 to -0.26 V in 0.1 mol/L H2SO4 solutions to the steady state. For comparison, however, experiments were also carried out with CV in the second step (2 mol/L K2PtCl4+0.1 mol/L K2SO4 aqueous solution with 190 cycles: these proved to be the optimal conditions). The morphology of 3D Au/MWCNTs electrode was characterized by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The voltammetric behavior of hemoglobin (Hb) on 3D Au/MWCNTs-Nafion has been investigated in 10 nmol/L Hb solution (pH=6 PBS) by cyclic voltammetry (CV) and current-time method (CT). Compared with Au+MWCNTs-Nafion (+means mix together), Au/MWCNTs-Nafion (uniform Au nanoparticle dispersion of MWCNTs, which was obtained when the second step adopts cyclic voltammetry instead of potential-step method), 3D Au/MWCNTs-Nafion gave a higher peak current and better reversibility. The higher sensitivity and lower detection limit show that 3D Au/MWCNTs-Nafion can offer a conductive microenvironment for the immobilized Hb to achieve direct electrochemistry. The average coverage (Γ) of Hb immobilized on 3D Au/MWCNTs-Nafion was calculated to be 7.65×10-9 mol·cm-2, testifies a high surface-to-volume ratio. Electron transfer rate constant (kS) was calculated to be 1.8 s-1, which was proved 3D Au/MWCNTs-Nafion is more conducive to direct electron transfer between Hb and the electrode. Hb/Au/MWCNTs-Nafion potential application towards the electrocatalytic reduction of H2O2 was also conducted to show immobilized Hb exhibits excellent biocompatibility and stability. Our work points to a new path for the preparation of 3D Au/MWCNTs nanocomposites, which are promising as electrocatalysts in direct electrochemistry of Hb.