Synthesis of nanocrystalline photocatalytic TiO 2 thin films and particles using sol–gel method modified with nonionic surfactants

Abstract

A simple sol–gel route has been developed for the preparation of nanocrystalline photocatalytic TiO 2 thin films and particles at 500 °C. The synthesis involved a novel chemistry method employing nonionic surfactant molecules as a pore directing agent along with acetic acid-based sol–gel route without direct addition of water molecules. This study investigated the effect of surfactant type and concentration on the homogeneity, morphology, light absorption, dye adsorption and degradation, and hydrophilicity of TiO 2 films as well as on the structural properties of the corresponding TiO 2 particles. The method resulted in the synthesis of mesoporous TiO 2 material with enhanced structural and catalytic properties including high surface area, large pore volume, pore size controllability, small crystallite size, enhanced crystallinity, and active anatase crystal phase. The prepared TiO 2 thin films were super-hydrophilic and possessed thermally stable spherical bicontinuous mesopore structure with highly interconnected network. Highly porous TiO 2 films prepared with polyethylene glycol sorbitan monooleate surfactant exhibited four times higher photocatalytic activity for the decoloration of methylene blue dye than the nonporous control TiO 2 films prepared without the surfactant. This sol–gel method modified with surfactant templates is useful in the preparation of nanostructured anatase TiO 2 thin films with high photocatalytic activity and desired pore structure.