Preparation and characterization of polypyrrole/TiO2 nanocomposites for photocatalysis

U rada su istraživani uvjeti sinteze vodljivog polimera polipirola (PPy) te sinteze in-situ nankompozitnih fotokatalizatora (PPy/Ti), PPy uz prisustvo nanočestica titanijeva dioksida (TiO2). Uvjeti sinteze bili su jednaki onima za čisti PPy. Struktura molekula PPy modificirana je tako da su uzorci sintetizirani uz različitu koncentraciju oksidansa (željezova klorida), te različito vrijeme sinteze (90 i 180 min). Efikasnost fotokatalitičke razgradnje organskog azo bojila (Reactive Red 45) kao onečišćenja vode, odnosno stupanj njegova uklanjanja iz vodene otopine praćena je mjerenjem apsorbancije UV/Vis spektroskopijom. Istraživani uzorci okarakterizirani su infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR), cikličkom voltametrijom (CV) i termogravimetrijskom analizom (TGA) kojom je određen udio polimera u nanokompozitu. Iz rezultata istraživanja uvjeta sinteze vodljivog polimera polipirola se može zaključiti da promjena uvjeta sinteze utječe na stupanj konverzije i strukturu molekula pirola, ali i na veličinu molekulskih masa što ima za posljedicu promjenu svojstava polipirola. Iz rezultata fotokatalitičke aktivnosti vidljivo je da veću fotokatalitičku aktivnost imaju sintetizirani uzorci nanokompozita PPy/TiO2 u usporedbi s čistim polipirolom.In this work conditions of synthesis of conductive polymer polypyrrole (PPY) and in-situ synthesis of nanocompositesphotocatalyst (PPY/Ti), PPY in the presence of nanoparticles of titanium dioxide (TiO2) are investigated. The synthesis conditions were identical to those for pure PPy. The molecular structure of PPY was modified that the samples are synthesized with different concentration of the oxidant (iron chloride), and sample were synthesised for different times (90 and 180min). The efficiency of decomposition of organic azo dyes (Reactive Red 45) as a model of water pollution,respectively the extent of its removalfrom aqueous solutions was monitored by measuring the absorbance of UV/Vis spectroscopy. Studied samples were characterized by infrared spectroscopy with Fourier transform (FTIR), cyclic voltammetry (CV) and thermogravimetric analysis (TGA) which determines the proportion of the polymer in nanocomposites. From the results of studied conditions of synthesis for the conducting polymer polypyrrole synthesis can be concluded that the change in conditions affects the degree of conversion, structure of pyrrole molecules and the size and molecular weight, which all results ina change of polypyrrole properties. From the results of photocatalytic activity it is evident that photocatalytic activity of the synthesized nanocomposites polypyrrole/TiO2 samples is significantly higher compared to pure polypyrrole