Synthesis, Characterization, Electronic Structure, and Photocatalytic Activity of Nitrogen-Doped TiO₂ Nanocatalyst

TLDR

Nitrogen‑doped TiO₂ nanocatalyst was synthesized by a chemical route using TiCl₃ as precursor, producing spherical particles of uniform size. The N‑doped TiO₂ exhibits a visible‑light absorption onset at 550 nm, a reduced band gap with N 2p states at the valence‑band edge, N incorporated as N–Ti–O, and outperforms Degussa P25 in methylene‑blue photodegradation under visible light.

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.