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

Abstract

The polyaniline (PANI)/TiO 2 nanocomposites have been successfully synthesized via a hydrothermal method and followed by a low-temperature calcination treatment process. We find that such a PANI/TiO 2 nanocomposite exhibits higher photocatalytic activity and stability than bare TiO 2 and TiO 2- x N x toward the liquid-phase degradation of methyl orange (MO) under both UV and visible light (420 nm < λ < 800 nm) irradiation. More noteworthy, the PANI/TiO 2 photocatalyst still perform good activity toward MO and 4-chlorophenol (4-CP) under the longer wavelength of light (550 nm < λ < 800 nm). The total organic carbon (TOC) tests show that the mineralization rate of MO and 4-CP over PANI/TiO 2 are apparently higher than bare TiO 2 under the irradiation of both UV and visible light. The presence of synergic effect between PANI and TiO 2 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.