Stable plasmonic Ag/AgCl–polyaniline photoactive composite for degradation of organic contaminants under solar light

A series of novel plasmonic photocatalysts of Ag/AgCl-polyaniline (Ag/AgCl-PANI) were successfully synthesized by deposition-precipitation reaction followed by a photo-reduction method. The prepared photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy, photoluminescence emission spectroscopy, and thermogravimetric analysis. Ag/AgCl-PANI was used to degrade methylene blue (MB) under simulated solar light. The effects of different parameters such as PANI content, initial pH and concentration of the MB solution, and catalyst dosage on the photo-degradation efficiency were assessed. Ag/AgCl-PANI plasmonic photocatalyst displayed much higher photocatalytic efficiency than the pure PANI or Ag/AgCl. The improved photocatalytic performances of the prepared photocatalysts were attributed to the high absorbance in the visible-light region, high surface areas of catalysts and the effective synergism of hetero-junction structure formed at the interface between Ag/AgCl and PANI, leading to improved separation of the photo-generated electron-hole pairs. A possible mechanism for the photo-degradation of MB molecules under simulated solar irradiation was suggested based on trapping experiments.