A facile synthesis of well-defined titania nanocrystallites: Study on their growth, morphology and surface properties

Abstract

The fast and simple synthesis of anatase nanocrystallites by the low-temperature hydrolysis of titanium (IV) alkoxides in the hydrogen peroxide solution followed by calcination of the amorphous titania peroxo-product at temperature in the range 300–450°C was designed and studied. The phase composition and crystallite-size were evaluated from X-ray diffraction data by the advanced whole powder pattern modeling method together with the crystallite-size distribution and microstructure parameters such as the defect density. Besides that, the textural and surface properties, skeletal density, particle morphology and the purity of nanopowders were determined by nitrogen physisorption, helium pycnometry, mercury porosimetry, XPS, FESEM and the organic elementary analysis. The pure anatase nanocrystallites with the uniform globular structure and the narrow crystallite-size distributions were prepared at the significantly lower temperature (300°C) in comparison with the conventional chemical methods. The size and shape of anatase crystallites were tailored by the calcination temperature and the type of titanium (IV) alkoxide. Titania nanocrystallites with the excellent uniformity were produced from titanium (IV) n-butoxide-type precursor. Correlation between the crystallite growth and the porous structure was observed up to temperature about 400°C. Above this temperature the crystallite size monotonically increases, whereas the specific surface area is reduced steeply.