The influence of preparation method, nitrogen source, and post-treatment on the photocatalytic activity and stability of N-doped TiO 2 nanopowder

Abstract

NH 3 plasma, N 2 plasma, and annealing in flowing NH 3 were used to prepare N doped TiO 2, respectively. XRD, UV–vis spectroscopy, N 2 adsorption, FT-IR, Zeta-potential measurement, and XP spectra were used to characterize the prepared TiO 2 samples. The nitridation procedure did not change the phase composition and particle sizes of TiO 2 samples, but extended its absorption edges to the visible light region. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activity and stability of TiO 2 prepared by NH 3 plasma were much higher than that of samples prepared by other nitridation procedures. The visible light activity of the prepared N doped TiO 2 was improved by increasing the lattice-nitrogen content and decreasing adsorbed NH 3 on catalyst surface. The lattice-nitrogen stability of N-doped TiO 2 samples improved after HCl solution washing. The possible mechanism for the photocatalysis was proposed.