Preparation And Application Of Carbon Nanotubes/ Polyaniline Chemically Modified Electrode

In this thesis, the grown in situ carbon nanotube/polyaniline chemically modified electrode (GSCNTs/PANI-CME) was prepared and applied in the field of electrochemical detection. The main researches are as follows:(1) A grown in-situ carbon nanotubes/polyaniline chemically modified electrode (GSCNTs/PANI-CME) was synthesized via a liquid ethanol flame. First, nickel catalyst was obtained by electrochemical deposition on a graphite electrode (GE) surface, followed CNTs were grown in-situ to obtain CNTs chemically modified electrode (GSCNTs-CME) via a liquid ethanol flame. Then, the grown CNTs were acid treated to carboxylate and remove nickel particles. Finally, PANI was prepared in-situ by electrochemical polymerization on the GSCNTs-CME to obtain GSCNTs/PANI-CME. The obtained electrodes were characterized by optical microscope and scanning electron microscopy. The electrochemical performance of the obtained GSCNTs/PANI-CME were characterized by cyclic voltammetry (CV) using the [Fe(CN)6]3-/[Fe(CN)6]4-solution. The results showed there was a layer of nickel on the pretreated GE surface after direct current electrochemical deposition. CNTs with the diameter of about 40 nm grew uniformly on the GE surface and the original tubular structure was remained. PANI was uniformly coated on the surface of CNTs in the obtained composite, which was a typical three-dimensional network structure. The GSCNTs/PANI-CME had good current responsive sensitivity and good testing result accuracy.(2) A grown in-situ carbon nanotubes/polyaniline chemically modified electrode (GSCNTs/PANI-CME) was synthesized for the electrochemical detection of ascorbic acid (AA), using catalytic chemical vapor deposition(CCVD). First, nickel catalyst was obtained by electrochemical deposition on a graphite electrode (GE) surface, followed CNTs were grown in-situ to obtain CNTs chemically modified electrode (GSCNTs-CME) by CCVD. Then, the grown CNTs were acid treated to carboxylate and remove nickel particles. Finally, PANI was prepared in-situ by electrochemical polymerization on the GSCNTs-CME to obtain GSCNTs/PANI-CME. The obtained electrodes were characterized by optical microscope, scanning electron microscopy and cyclic voltammetry. The results showed CNTs grew uniformly on the GE surface and the original tubular structure was remained. PANI was uniformly coated on the surface of CNTs in the obtained composite, which was a typical three-dimensional network structure. The GSCNTs/PANI-CME exhibited an excellent electrocatalytic activity to AA. The oxidation peak current was increased linearly with the concentration of AA in the range from 1.0×10-6 mol L-1 to 4.5×10-4 mol L-1, with a detection limit of 1.0×10-7 mol L-1 (S/N= 3). The experimental data showed that the obtained electrode was selective, stable and reproducible. The recoveries were between 97.4% and 102.1%.(3) A grown in-situ carbon nanotubes/polyaniline chemically modified electrode (GSCNTs/PANI-CME) was synthesized via sulfuric acid and polyacrylic acid doped. First, nickel catalyst was obtained by electrochemical deposition on a graphite electrode (GE) surface, followed CNTs were grown in-situ to obtain CNTs chemically modified electrode (GSCNTs-CME) by catalytic chemical vapor deposition. Then, the grown CNTs were acid treated to carboxylate and remove nickel particles. Finally, PANI was prepared by electrochemical polymerization on the GSCNTs-CME with sulfuric acid and polyacrylic acid doped, obtaining GSCNTs/PANI-CME. The obtained electrodes were characterized by cyclic voltammetry. The results showed that the GSCNTs/PANI-CME had the best electrochemical performance when the polypropylene acid doping amount was 5 mg/mL and the polymerization number was 10 circle. GSCNTs/PANI-CME had good current responsive sensitivity and good testing result accuracy. When the pH of the solution ranged between 2-10, the maximum value and the minimum value of the oxidation peak current was only a difference of 8.1%, indicating that the GSCNTs/PANI-CME can be used in alkaline environment and be applied in electrochemical sensor field.