Plasma enhanced chemical vapor deposition of TiO2 films on silica gel powders at atmospheric pressure in a circulating fluidized bed reactor

Abstract

Anatase TiO2 thin films were deposited on silica gel powders by plasma enhanced chemical vapor deposition (PECVD) method in a circulating fluidized bed (CFB) reactor using ITIP [Ti(O-i-C3H7)(4)] and oxygen without any post-treatment. The optimum solid circulation rates were determined for the stable He-plasma glow discharge with He fluidizing gas. The optimum deposition conditions of TiO2 thin films by PECVD with helium gas were determined with variation of oxygen and argon concentrations and TTIP flow rate at a deposition temperature of 250 degrees C. Based on the X-ray diffraction, scanning electron microscope (SEM) and Raman scattering spectroscopy analyses, the optimum condition for anatase phase deposition are found to be 3.6 vol.% of O-2, 0.4 g/min of TTIP and 8.18 vol.% of At. The prepared powders exhibit good photocatalytic activity to decompose methylene blue aqueous solution under UV light. (C) 2009 Elsevier B.V. All rights reserved.