Synthesis, characterization, electronic structure, and photocatalytic activity of nitrogen-doped TiO₂ nanocatalyst

Abstract

Nitrogen-doped TiO₂ (N-TiO₂) nanocatalyst with spherical shape and homogeneous size has been synthesized through a chemical method using TiCl₃ as precursor. The light absorption onset shifts from 380 nm on pure TiO₂ to the visible region at 550 nm with N-TiO₂. A clear decrease in the band gap and the nitrogen 2p states on the top of the valence band on N-TiO₂ (compared to TiO₂) is deduced from the optical absorption spectroscopy results. The chemical nature of N has been evolved as N-Ti-O in the anatase TiO₂ lattice as identified by X-ray photoelectron spectroscopy (XPS). Photocatalytic decomposition of methylene blue has been carried out both in the UV and in the visible region and N-TiO₂ shows higher activity than the Degussa P25 TiO₂ photocatalyst in the visible region.