Electrochemical property of multi-walled carbon nanotubes/chitosan composites by electrostatic interactions

Biocompatible multi-walled carbon nanotubes (MWCNTs)/chitosan(CS) composites were synthesized by electrostatic interactions between positively charged CS and negatively charged MWCNTs colloid solution functionalized with nitric and sulfate acid. The effect of pH value on the viscosity of MWCNTs/CS colloid could be controlled by adjusting the pH value, which was determined by the charge type and potential strength. The electrochemical properties of MWCNTs/CS composites were also studied by CHI650C electrochemical workstation. The MWCNTs/CS composites were characterized by using Fourier transform infrared spectrometer (FT-IR), High-Resolution Transmission Electron Microscope (HRTEM) and thermal gravimetric analysis (TGA). The experimental results showed that the stable and homogeneous MWCNTs/CS composites were obtained at pH 5 owing to existing strong electrostatic attraction. The weight ratio of CS polymer attached on the surface of MWCNTs was around 45wt%, and the thickness of CS grafted on the surface of MWCNTs was about 4nm. The electrocatalytic activity of nitrite (NO₂-) decorated with MWCNTs/CS composites glass-carbon electrode was tested, and the results indicated that the MWCNTs/CS modified electrode possess excellent electrocatalytic ability.