Electrochemical Behavior Of Carbon Nanotubes And Their Derivatives

Carbon nanotubes have exceptional good properties, such as:good electron transport capability, high aspect ratio, large surface area and strong adsorption ability. We make use of their good performance to conduct a series of studies on the carbon nanotubes derivaties.The electrodes modified with multiwalled carbon nanotubes carrying Fe3O4 beads (Fe3O4/MWCNTs) were fabricated and their electrochemical behavior was investigated by cyclic voltammetry. Meanwhile, the sensitivity to H2O2 (aq) of these electrodes was also explored. The results indicated that the electrodes coated with Fe3O4/MWCNTs exhibit high sensitivity to H2O2 (aq) with a detectable concentration of 1.6×10-9 mol·dm-3, multi-wall carbon nanotubes of high aspect ratio and the special electronic structure plays a very important role, The results implied carbon nanotubes-based biosensing devices was promising for the development of biosensing devices.Alanine ethyl ester modified multi-walled carbon nanotubes (MWNT-Ala) were prepared and characterized with a Fourier transform infra-red (FT-IR) spectrometer. The electrochemical behavior of D-and L-tryptophan on the electrodes coated with MWNT-Ala was investigated by cyclic voltammetry. Meanwhile, in order to further understand the mechanism of electrochemical process, the electrochemical behavior of D-and L-tryptophan on the bare glassy carbon electrodes and the electrodes coated with multi-walled carbon nanotubes possessing carboxyl groups (MWNT-COOH) was also discussed, respectively. The results show that the electrodes coated with MWNT-Ala can recognize the L/D-tryptophan chiral isomer, which is due to the introduction of chrical alanine ethyl ester moieties on the multi-walled carbon nanotubes. Furthermore, the enantioselectivity of the electrodes coated with MWNT-Ala was studied as a function of pH of the solution and the scan rate. Its selectivity is best at pH=6.4, and with the scan rate increased, the selectivity also increased.TPP-CNTs and ZnTPP-CNTs were prepared using theπ-πinteration of porphyrin macrocycle and CNTs, and characterized with UV-vis absorption spectra, fluorescence spectra and IR. The electrochemical and photoelectrochemical behaviors of TPP-CNTs and ZnTPP-CNTs modified electrodes were investigated by cyclic voltammetry and impedance. Meanwhile, in order to understand the mechanism, the electrochemical and photoelectrochemical behaviors of CNTs modified with electrodes were also discussed respectively. The result showed that TPP-CNTs modified with electrode had better charge-transfer ability than that of the ZnTPP-CNTs modified with electrodes. This may be ascribed to the influence of the central metal ion, which leads to worse planarity. Therefore, theπ-πinteraction between porphyrin molecules and carbon nanotubes is weakened, leading to the efficiency of electron transfer lower. We can speculate the geometric structure of porphyrin molecule may play an important role in the electron transfer process of the porphyrin modified carbon nanotubes.