Electrochemical Behaviour of (n‐Bu₄N)₄[AsVMo₁₁O₄₀] and (n‐Bu₄N)₄[AsV₂Mo₁₀O₄₀] Doped PEDOT Film and Its Quartz Crystal Microbalance Studies

Keggin‐type polyoxometalates (POMs), (n‐Bu 4 N) 4 [AsVMo 11 O 40 ] (AsVMo 11 ) and (n‐Bu 4 N) 4 H[AsV 2 Mo 10 O 40 ] (AsV 2 Mo 10 ), have been immobilised with the conducting polymer poly (3,4‐ethylenedioxythiophene) (PEDOT) on the surface of the glassy carbon electrode via chronocoulometry technique. The voltammetric behaviour of these modified electrodes was investigated with cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The resulting films showed the surface adsorbed behaviour and dependence on the pH of the electrolyte solution. By using AC impedance, it was found that the resulting POM‐doped PEDOT films were highly conductive. The redox switching stability of the polymer films was investigated, and it was found that the AsVMo 11 /PEDOT hybrid film is significantly more stable for continuous potential sweep than the AsV 2 Mo 10 /PEDOT hybrid film. Additionally, the EQCM measurements confirm that during the redox potential cycling, the anions in the supporting electrolyte replace the POMs anion doped onto the film.