engleski

Synthesis of Poly(3, 4- ethylenedioxythiophene)/TiO2 Photocatalytic Polymer Nanocomposites

Environmental problems associated with water pollution have persistently been an important issue over recent decades, correlated negatively with the health and ecosystem. Photocatalysis is established as an effective and sustainable water treatment technology offering a perspective for the degradation of many organic water pollutants, converting them to biodegradable compounds or completely mineralizing them into carbon dioxide and water. Titanium dioxide, TiO2, is one of the most important photocatalyst, which is widely used due to its chemical stability and high photocatalytic activity. It is also inexpensive and harmless to the human population and the environment. However, relatively high recombination rate of electron-hole pair in excited TiO2 restricts its photocatalytic activity thus hindering its practical application in the water treatment processes. Conducting polymers with extended π-conjugated electron system and satisfactory environmental stability can act as stable photo-sensitizer to sensitize TiO2. As typical n-type semiconductors, conducting polymers can absorb a broad spectrum of ultraviolet and visible light (190–800 nm) irradiation1 . Because of that the main goal of this work was to exploit the sensitizing capacities of conducting polymers to produce TiO2-based photocatalyst with enhanced photocatalytic properties. For this purpose nanocomposite of poly(3, 4- ethylenedioxythiophene) (PEDOT) and TiO2 was synthesized by oxidative chemical polymerization with two different oxidants, FeCl3 and ammonium persulfate (APS). Polymerization was carried out in batch reactor at room temperature for 24 h in nitrogen atmosphere with HCl as the dopant. To determine effect of oxidant on structure of synthesized PEDOT/TiO2 nanocomposite infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used. To determine polymerization degree TG analysis was used. FT-IR results showed typical vibrations for PEDOT and Ti-O, and thus confirmed successful synthesis of polymer photocatalyst nanocomposites. A significant influence of oxidant agent on the morphology had been confirmed by XRD and SEM. Samples synthesized with FeCl3 showed highly crystalline morphology while samples prepared with APS had more sphere-like amorphous morphology. The results demonstrate that the redox potential of used oxidizing agents has a key role in tailoring the properties of PEDOT nanocomposites.

poly(3 ; 4-ethylenedioxythiophene) ; titanium dioxide ; photocatalysis ; polymer nanocomposites

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