الفهرس 
Water pollutantsOnly 14 pages are availabe for public view
 |  | from | 115 |  |  |
| | | from | 115 | | |
Abstract
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 materials were characterized by X-ray diffraction, field emission scanning electron microscopy with energy dispersive X-ray spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, the specific surface areas measure using BET equation, 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.
The photocatalytic activity and stability of Ag/AgCl is improved after introducing PANI into the prepared photocatalyst. PANI improves the surface area and increases the visible-light absorption ability of the prepared photocatalysts. Furthermore, the enhanced photocatalytic activity and stability of the photocatalysts can be attributed to the presence of synergistic effect of hetero-junction structure formed in the interface between Ag/AgCl and PANI which is effective in separation of photoexcited electron–hole pairs.
Ag/AgCl-PANI(5%) showed the highest photocatalytic performance with a rate constant ~ 4 times higher than that of the pure Ag/AgCl. However, increasing the percentage of PANI to more than 5% led to a reduction in electron–hole separation efficiency, decreasing the surface area of the
photocatalyst, and can cover the surface of Ag/AgCl and hinders the light
absorption intensity of AgCl, thus decreasing its photocatalytic activity.
The trapping of oxidizing species during MB photo-degradation helped in
the estimation of a possible mechanism for the photo-degradation of MB
molecules under simulated solar irradiation. It was found that the hydroxyl
radicals OH• have negligible oxidation effect compared with holes h and
superoxide radicals 2 O•.
The prepared photocatalyst exhibited high stability toward MB dye photodegradation.
This result validates that Ag/AgCl-PANI(5%) composite is a
kind of active and stable photocatalyst and can be used for long-term
practical application.