Chitosan-assisted fabrication and electrocatalytic activity of the composite film electrode of heteropolytungstate/carbon nanotubes

A novel chemically modified electrode based on the immobilization of heteropolytungstate in carbon nanotubes–chitosan (CNTs–chitosan) composite film by one step self-assembly technique was fabricated. Chitosan was chosen as a natural polymer for dispersing CNTs to form a stable CNTs–chitosan composite, which provided an interface containing amino groups for assembling [P2W18O62]6− (abbr. P2W18) by electrostatic interactions. The CNTs–chitosan composite film was investigated and characterized by infrared spectroscopy (IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The CNT–chitosan film provides a high active area and good conduction pathway, and enhances the adsorptive capability of P2W18 molecules on the film. The electrochemical behavior of the P2W18/CNTs–chitosan/GCE was studied in detail, including scan rate, pH dependence, and stability. The CV and amperometry studies demonstrate that the P2W18/CNTs–chitosan/GCE has fast response and good electrocatalytic activity for the reduction of S2O82− and IO3− anions in acidic aqueous solution.