Flame synthesis of TiO 2 nanoparticles with high photocatalytic activity

Abstract

Growth behaviour of TiO 2 particles, which has significant influence on their crystallinity and surface area, has been controlled by varying the process parameters of the flame aerosol synthesis. An existing method to determine the crystallinity of the powder has been modified which facilitates comparison of the degree of crystallinity of the nanoparticles synthesized by various methods. Resultant TiO 2 nanoparticles were characterized by XRD and nitrogen physisorption to determine the degree of crystallinity quantitatively and surface area, respectively, and the decomposition rate of an industrial dye, methylene blue, has been taken as the measure of the photocatalytic activity (PCA). TiO 2 nanoparticles showed improved photocatalytic activity compared to the commercial photocatalyst, Degussa P25. This is attributed to the increased degree of crystallinity and surface area of the TiO 2 nanoparticles compared to Degussa P25. The results of this study elucidate the importance of the gas-phase processes and strategy to synthesize highly active TiO 2 photocatalysts in a single step. Moreover, difference in the PCA of the nanoparticles synthesized by the similar gas-phase routes has been shown and the particles are tailor-made for improved PCA in the present study.