Preparation of polypyrrole/TiO2 nanocomposites with enhanced photocatalytic performance

A simple in situ method was developed to synthesize polypyrrole (PPy)/TiO2 nanocomposites having high photocatalytic activity under simulated solar light. The structure and morphology of the PPy/TiO2 nanocomposites were characterized by X-ray powder diffraction (XRD), transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, and Fourier transform infrared spectroscopy. The visible light photocatalytic properties of the nanocomposites were demonstrated by Rhodamine B degradation and by the production of methanol from CO2. The XRD analysis showed that the coating of PPy did not change the crystallinity of the TiO2. The UV-vis diffuse reflectance spectra indicated that the light adsorption range of the TiO2 was enlarged after modification. Energy-dispersive X-ray spectroscopy analysis confirmed the presence of PPy and TiO2 in the nanocomposite catalyst. The RhB degradation using the nanocomposites was increased by 41% and the methanol yield was enhanced by 34 wt% in comparison with those obtained with pure TiO2. The improvements were considered to originate from the increased separation efficiency of hole electron pairs from TiO2 and the enhancement of the light adsorption range by the introduced PPy. (C) 2015 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. All rights reserved.