An Experimental Study of the Synthesis of Ultrafine Titania Powder in Plasmachemical Flow-Type Reactor

Abstract

Abstract Methods for controlling the synthesis of the submicron (including nanosized) powder of titanium dioxide (titania, TiO2) in a setup with a plasmachemical flow reactor were investigated. The synthesis of titania particles from gaseous titanium tetrachloride (TiCl4) in the plasmachemical reactor by the chloride method was experimentally studied. The processes of formation and growth of particles depending on the type of the plasma-forming gas, flow rates of TiCl4; and the quenching gas (air), reactor length, and mean-mass temperature in the reaction zone were considered. When using nitrogen as heat-carrying gas, a new approach of titania powder synthesis based on combining of reaction zone and quenching zone has been applied. Under these non-equilibrium conditions and substantial temperature gradients, this method enabled us to synthesize reproducibly ultrafine titania powders (30–50 nm) with a high content (80–87%) of metastable anatase crystal lattice. The results reveal that the powder properties can be efficiently controlled, i.e., one setup can produce titania with a required particle size and a type of the crystal lattice: anatase (A) or rutile (R). The experimental data are found to agree well with the results of numerical calculations.