Photocatalytic Activities of PET Filaments Deposited with N-Doped TiO2 Nanoparticles Sensitized with Disperse Blue Dyes

In this study, the enhanced photocatalytic activities of polyethylene terephthalate (PET) filaments deposited with N-doped Titanium dioxide (TiO2) nanoparticles sensitized with water insoluble disperse blue SE–2R dye were investigated. The PET filaments were loaded with two types of N-doped TiO2 nanoparticles, one with and the other without being sensitized with disperse blue SE–2R dye, in one-pot hydrothermal process respectively. The differences in photocatalytic activities between the N-doped TiO2 and the dye-sensitized N-doped TiO2 nanoparticles when exposed to both UV rays and visible lights were analyzed and compared by using their photodegradations of methylene blue (MB) dye. It was demonstrated that the disperse blue dye facilitated the electron–hole separation in N-doped TiO2 nanoparticles faster under UV irradiation than that under visible light irradiation. The enhanced photocatalytic activity of the PET filaments loaded with dye-sensitized N-doped TiO2 nanoparticles exposure to UV irradiation, in comparison with that under visible light irradiation, was attributed to both improved light absorption capacity and high separation efficiency of photo-generated electron–hole pairs. Furthermore, the conduction band and band gap of the PET filaments deposited with N-doped TiO2 nanoparticles sensitized with disperse blue SE–2R dye were influenced by the wavelength of light sources, while its valence band was not affected. The PET filaments deposited with dye-sensitized N-doped TiO2 nanoparticles have a potential application to degrade organic pollutants.