Structure and properties of solid-state synthesized poly(3,4-propylenedioxythiophene)/nano-ZnO composite

Poly(3,4-propylenedioxythiophene)/nano-Zinic Oxide (PProDOT/ZnO) composites with the content of 3-7 wt% nano-ZnO were synthesized by the solid-state method with FeCl3 as oxidant. The structure and morphology of the composites were characterized by Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical performances of the composites were investigated by galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The photocatalytic activities of the composites were investigated by the degradation of methylene blue (MB) dyes in aqueous medium under UV light irradiation. The results from FTIR and UV-vis spectra showed that the PProDOT/ZnO composites were successfully synthesized by solid-state method, and nano-ZnO had great influences on the conjugation length and oxidation degree of the polymers. Furthermore, the PProDOT/5 wt%ZnO had the highest conjugation and oxidation degree among the composites. The results of XRD analysis indicated that there were some FeC14− ions as doping agent in the PProDOT matrix, and the content of ZnO had no effect on diffraction pattern of PProDOT. Morphological studies revealed that the pure PProDOT and composites had similar morphological structure, and all the composites displayed an irregular sponge like morphology. The results of electrochemical tests showed that the PProDOT/5 wt%ZnO had a higher electrochemical activity with a specific capacitance value of 220 F g−1 than others. The results from photocatalytic activities of the composites indicated that the PProDOT/5 wt%ZnO had better photocatalytic activity than other composites.