Composite films of polyaniline and molybdenum oxide formed by electrocodeposition in aqueous media

Composite films of polyaniline (PANI) and molybdenum oxide (MoOx) were afforded through a convenient route of electrocodeposition from aniline and (NH4)(6)Mo7O24. The composite films showed characteristic redox behaviors of PANI and MoOx, respectively, on the cyclic voltammograms. Chlorate and bromate were catalytically electroreduced with an enlarged current on the composite film at a potential ca. 0.2 V more positive than that on MoOx. The potential window for the composite film to display pseudocapacitive properties in 1.0 mol center dot dm(-3) NaNO3 was -0.6 similar to 0.6 V vs SCE. The cathodic potential limit shifted at least 0.4 V negatively from that of polyaniline (PANI)-based materials reported so far. The specific capacitance was 363.6 F center dot g(-1) when the composite film was charged-discharged at 1.5 mA center dot cm(-2), about two times of that of the similarly prepared PANI. The composite film was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Molybdenum existed in a mixed state of +5 and +6 in the composite film based on XRD and XPS investigations.