Preparation and characterization of high-surface-area titanium dioxide by sol-gel process

One of the important ways to improve photocatalytic efficiency is to prepare catalyst with enhanced surface area. In this work, titanium dioxide (TiO2) nanoparticles having enhanced surface area were synthesized under the interference Of SiO2. The mixed oxide, SiO2-TiO2 (10% mol% Si), was prepared by a sol-gel procedure using titanium tetran-butoxide as Ti-precursor. The commercial SiO2 nanoparticles were added into the TiO2 sols after hydrolysis. After condensation and calcination heat treatment, the SiO2-TiO2 nanoparticles were obtained. To achieve the purpose of obtainincy the high-surface-area TiO2, the SiO2 was removed subsequently by aqueous NaOH solution. The TiO2 products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), electron spectroscopy for chemical analysis (ESCA), and by N-2 adsorption-desorption isotherm. A fine mesoporous structure was formed for as-prepared TiO2) after calcination at 400 degrees C and the average pore diameter was about 7 nm. The porous TiO2 products possess mixing phases of anatase and rutile. Phase transformation from anatase to rutile occurred when the samples were calcined. The phase transition temperature is sensitive to the silicon content. The particle size of similar to 43 nm remained constant upon calcinations from 500 to 700 degrees C. The specific surface area was increased up to 66% compared to regular TiO2 samples that were prepared by the similar sol-gel procedure. The porous TiO2 nanostructures exhibited enhanced photocatalytic performance to decompose methylene blue under UV irradiation.