Synthesis and characterization of different binary and ternary phase mixtures of mesoporous nanocrystalline titanium dioxide
Abstract
Different phase compositions of mesoporous nanocrystalline TiO2 (meso-nc-TiO2), comprised of anatase (16-100%), rutile (0-70%) and brookite (0-52%) were obtained by sol-gel synthesis with or without hydrothermal treatment (HTT) by means of titanium tetrabutoxide and dibenzo-18-croun-6 as structure-forming agent in the presence of HCl. It was shown, that small amounts of surfactant and/or lanthanum salt as well as HTT determine phase composition and texture of meso-nc-TiO2.
All samples were calcined at 500 C and characterized by SEM, TEM, XRD and N-2-adsorption/desorption isotherms. It has been established that photocatalytic properties of almost all obtained samples significantly exceed the photocatalytic activity of Evonik P-25 TiO2 in gas phase ethanol oxidation.
The most active sample is characterized by phase composition of anatase (97%)-rutile (3%). It is obvious, that decrease of photocatalytic activity of sample was affected by decrease of anatase phase content.
It was shown that the specific surface area of the sample is not a key factor affecting the activity of mixed-phase meso-nc-TiO2 samples in the process of ethanol oxidation.