Characterization and evaluation of fibrous SrTiO 3 prepared by hydrothermal process for the destruction of NO

Abstract

Fibrous SrTiO 3 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. SrTiO 3 existed as two different morphologies of particles, i.e., fibrous particles and nanosized particles which attached to the surface of former ones. SrTiO 3 seemed to be formed by two different ways. One way is a direct reaction between H 2Ti 4O 9 and Sr(OH) 2 and the other is a two-step reaction involving transformation of H 2Ti 4O 9 to monoclinic TiO 2 followed by a reaction with Sr(OH) 2. Fibrous nitrogen doped SrTiO 3, which exhibited excellent visible light responsive photocatalytic activity, was prepared by the heat treatment of fibrous SrTiO 3 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 SrTiO 3 were 2.4 and 1.3 times greater than those of spherical SrTiO 3 prepared by the solid-state reaction.