Highly Efficient Photocatalytic Degradation of Organic Pollutants by PANI-Modified TiO2 Composite

The polyaniline (PANI)/TiO2 nanocomposites have been successfully synthesized via a hydrothermal method and followed by a low-temperature calcination treatment process. We find that such a PANi/TiO2 nanocomposite exhibits higher photocatalytic activity and stability than bare TiO2 and TiO2,N-x toward the liquid-phase degradation of methyl orange (MO) under both UV and visible light (420 nm < lambda < 800 nm) irradiation. More noteworthy, the PANI/TiO2 photocatalyst still perform good activity toward MO and 4-chlorophenol (4-CP) under the longer wavelength of light (550 nm < lambda < 800 nm). The total organic carbon (TOC) tests show that the mineralization rate of MO and 4-CP over PANI/TiO2 are apparently higher than bare TiO2 under the irradiation of both UV and visible light. The presence of synergic effect between PANT and TiO2 is believed to play an essential role in affecting the photoreactivity. At last, the roles of active species in the photocatalytic process are compared by using different types of active species scavengers. Meanwhile, the degradation mechanism of the photocatalysts is proposed. It is hoped that our work could provide valuable information on the design of polymer modified semiconductor with more excellent properties and set the foundation for the further industrial application.