Characterization and evaluation of fibrous SrTiO3 prepared by hydrothermal process for the destruction of NO

Fibrous SrTiO3 particles were prepared by a hydrothermal reaction method using strontium hydroxide octahydrate and protonic layered tetratitanate as raw materials. The samples were characterized by X-ray diffraction, X-ray photoelectron spectrometer, scanning electron microscopy, nitrogen adsorption–desorption isotherm measurements and diffusion reflectance spectra. SrTiO3 existed as two different morphologies of particles, i.e., fibrous particles and nanosized particles which attached to the surface of former ones. SrTiO3 seemed to be formed by two different ways. One way is a direct reaction between H2Ti4O9 and Sr(OH)2 and the other is a two-step reaction involving transformation of H2Ti4O9 to monoclinic TiO2 followed by a reaction with Sr(OH)2. Fibrous nitrogen doped SrTiO3, which exhibited excellent visible light responsive photocatalytic activity, was prepared by the heat treatment of fibrous SrTiO3 under the flow of ammonia gas at 600 °C for 3 h. Under the irradiation of light with wavelengths larger than 400 and 290 nm, the photocatalytic activities of fibrous SrTiO3 were 2.4 and 1.3 times greater than those of spherical SrTiO3 prepared by the solid-state reaction.