| Polyaniline (PANI) is a typical conductive polymer, and has advantages of simplesynthesis, environmental stability, cheap, withstands high temperatures and high antioxidantperformance etc. So it has a wide application in the file of electrical、optical、magnetic、secondary battery、the sensor and so on. Nonetheless its Conjugate rigid structure makes itselfwith poor solubility and electrochemical performance in most organic solvents and neutraland alkaline conditions. The generalization and application of PANI is restrained to a certainextent. In order to improve the defects, PANI usually composites with other materials（Carbon nanotube). Carbon nanotube is a special carbon material with peculiar electricalconductivity, superior mechanical properties and high aspect ratio. It is easily composite withPANI and form network structure. What is more, the composite realizes the complementaryadvantages on the basis of keeping their respective fine characteristic. This will substantiallyincrease their electrochemical response effect. However, this biosensor has some defects inthe detection limit and sensitivity. So if we can add an auxiliary catalyst to bring a newbreakthrough for composite material modified electrodes.From this paper, we get a more excellent performance of PANI/CNT compositesmaterials. As an auxiliary catalyst，metal nanomaterial is simultaneously introduced toovercome the defects of components that eventually reach complementary advantagesbetween material or performance enhancement. The main research contents as follows:1. A homogeneous electroactive polyaniline (PANI) and multiwall carbon nanotube(MWNTs) composite film-modified electrode was fabricated by cyclic voltammetry and acasting method. The PANI/MWNTs/Nano-CeO2composite film-modified electrode wassystematically investigated by change their thickness, pH values of solution, the Mass ratio ofMWNTs to Nano-CeO2. These results showed that the PANI film, prepared for25cycles bycyclic voltammetry and the mass ratio of15:1, has better electrochemical activity, Nano-CeO2and Horseradish peroxidase, and high electroactivity in pH6.4buffer solution containingH2O2. The electrocatalytic behavior of H2O2indicated that the composite film have shortresponse time (<5s) for H2O2, and the plot of the response current vs. H2O2concentration waslinear over the concentration range from5.0×10-6to3.95×10-4mol/L (S/N=3), and detectionlimit of7.6×10-7mol/L(S/N=3).2. To change metal oxide, we acquired the HRP/PANI/MWNTs/Nano-NiO/GCcomposite film-modified electrode that apply to detect H2O2. It was characterized by cyclic voltammetry(CV)、 electrochemical impedance spectroscopy(EIS) and scanning electronmicroscopy(SEM). These results showed that the PANI film, prepared for30cycles by cyclicvoltammetry and the mass ratio of10:1, has better electroactivity in pH6.8buffer solutioncontaining H2O2. The electron transfer rate constant (Ks) was6.25s-1, the average surfacecoverage (Г) was3.6×10-5mol·cm-2and the apparent Michaelis-Menten constant (KM) was0.37μM. Moreover, the electrocatalytic behavior of H2O2indicated that short response time(<5s) for H2O2, and the plot of the response current vs. H2O2concentration was linear over theconcentration range from3.0×10-6to4.3×10-4mol/L, correlation coefficient was0.998anddetection limit of4.3×10-7mol/L.3. To change carbon-based material, we acquired the PANI/GEO/Nano-CeO2compositefilm-modified electrode. It was characterized by CV、EIS and typical current-time response（i-t）. These results showed that the PANI film, prepared for25cycles by cyclic voltammetryand the mass ratio of1:1, has better electroactivity activity in pH6.4buffer solutioncontaining H2O2. Kswas7.8s-1, Гwas5.8×10-8mol·cm-2and KMwas5.064μM. Moreover,the electrocatalytic behavior of H2O2indicated that short response time (<5s) for H2O2, andthe plot of the response current vs. H2O2concentration was linear over the concentrationrange from3.0×10-6~8.36×10-4mol/L, the correlation coefficient was0.997and detection limitof3.6×10-7mol/L. |
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