| Multiwall carbon nanotubes modified glassy carbon electrode (MWNTs-GCE) was prepared firstly in this thesis. Based on "seed medium growth method", gold nano-particles modified indium tin oxide electrode (GNP-ITO) was fabricated. Then gold nano-particles and multiwall carbon nanotubes were combined to modify indium tin oxide electrod (WMNTs-GNP-ITO). The morphology and surface structure of modified electrodes were characterized by transmission electron microscope image (TEM) and field emission scanning electron microscopy image (FE-SEM), and electrochemical behaviour were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Experiments results proved that MWNTs-GCE could be successfully used in simultaneous determination of three isomers of dihydroxybenzene, and MWNTs-GNP-ITO shows sepcial electric catalytic activity to the determination of single isomer of chlorophenol, and weak steady magnetic field has different effects on multi-walled carbon nanotubes and gold nano-particles modified electrodes. The main results are listed as following:1. MWNTs-GCE was fabricated by dropping10.0μA MWNTs solution on the surface of glassy carbon electrode. The existing form of the Multiwall carbon nanotubes in solution and the morphology of MWNTs-GCE were characterized respectively by TEM and FE-SEM. The electrochemical behavior of dihydroxybenzene isomers at the MWNTs-GCE electrode has been investigated by CV and DPV. It was found that MWNTs-GCE has excellent electrocatalyse and selectivity toward the electrochemical reaction of dihydroxybenzene isomers. At optimized conditions, within20μM-140μM, the anodal current of HQ, CC and RS were respectively found to be linear with their concentration, with the presence of10μM other two components. The linear regression equations were as follows:HQ, Ipa=0.0452c+6.8343(μA, r=0.9970); CC, Ipa=0.0543c+3.3886(μA, r=0.9966); RS, Ipa=0.0218c+1.8371(μA, r=0.9959), and the detection limit for HQ, CC and RS were1.0μM,1.3μM,4.7μM respectively. Furthermore, the modified electrode showed excellent reproducibility, anti-interference and long-term stability.2."Seed-mediated gold nano-particles growth method" was introduced to fabricate GNP-ITO. Based on GNP-ITO, multiwall carbon nanotubes were further modified on gold nano-particles to fabricate WMNTs-GNP-ITO. FE-SEM and electroalaylsis were employed to study the morphology and electrochemical performances of the modified electrodes. The modified electrodes were used for voltammetric determination of chlorophenol isomers by CV. It was found that WMNTs-GNP-ITO has excellent electrocatalyse to p-chlorophenol and m-chlorophenol, with the anodic peak current higher than that at GNP-ITO and MWNTs-ITO. However, cyclic voltammograms behavior of o-chlorophenol was almost the same as on WMNTs-GNP-ITO and MWNTs-ITO. Because of their anodic peak potential was too closing to each other, it was failed for simultaneous voltammetric determination of chlorophenol isomers.3. The influence of low steady magnetic field on multiwall carbon nanotubes, gold nano-particles and modified electrodes were studied. Under the environment of low steady magnetic field (0.3T), magnetized multiwall carbon nanotubes modified electrode (M-MWNTs-GCE) and magnetized gold nano-particles modified electrode (M-GNP-ITO) were fabricated by dropping method and "seed-mediated gold nano-particles growth method" severally. A variety of these modifieds electrodes was characterized with TEM, FE-SEM and electroalaylsis for topography and electrochemical properties. It was found that low steady magnetic field had little effect on the modifying process of multiwall carbon nanotubes, and the electrochemical behaviors of HQ, AA and PA on M-MWNTs-GCE were almost same as on MWNTs-GCE. However, to gold nanoparticles, low steady magnetic field could increase the diameter and sharpen gold nanoparticles. By contrasting the voltammetric behaviors of HQ, UA and PA on different electrodes, it was suggested that the catalysis of M-GNP-ITO was better than GNP-ITO. |
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