Synthesis of nonstoichiometric titanium dioxide in the hydrogen flow

Abstract

Nonstoichiometric titanium dioxide (TiO2-x) with different oxygen content was synthesized by sol?gel method and, subsequently, annealed in the hydrogen flow for one hour at 200, 400, 600, 800, or 1000 °C. Synthesized powders were studied by XRD, BET and DRS methods. X-ray phase analysis showed that an annealing at temperatures of 400 and 600 °C leads to the formation of the crystalline phase of anatase, but at 800 and 1000 °C annealing rutile phase is formed. Particle size increases from 10 to 45 nm at annealing. The diffuse reflectance spectra show a narrowing of the energy band gap from 3.3 down to 2.6 eV with increasing of annealing temperature. The specific surface area decreases from 306 to 1 m2/g after annealing.