Synthesis and photocatalytic activity of (S, N)-codoped TiO<SUB align="right">2 nanoparticles and nanotubes with high N and S contents

Abstract

(N, S)-codoped TiO2 nanotubes were fabricated by hydrothermally treating (N, S)-codoped TiO2 nanoparticles in a NaOH solution at 110°C for 20 h. The (N, S)-codoped TiO2 nanoparticles were synthesised by a solvothermal process with precursor solution containing titanium sulphate, thiourea, and dichloroethane. The (N, S)-codoped TiO2 nanoparticles and nanotubes were characterised with X-ray diffraction, transmission electron microscopy, and UV-vis. spectrophotometry. The nitrogen contents of the (N, S)-codoped TiO2 nanoparticles and nanotubes were reached to high values of 13.8 at.% and 12.9 at.%, and the sulphur contents were reached to 40.1 at.% and 40.6 at.%. This narrowed the band gaps of the nanoparticles and nanotubes and introduced indirect band gaps, and so respectively resulted in the extensions of the absorption edges to visible light and infrared region. The nanotubes shown larger specific surface area (3.4 times) and greater degradation efficiency to methyl orange than the nanoparticles.