Hydrothermal synthesis of TiO₂ hollow spheres using rapeseed pollen grains as template

TiO₂ precursor/pollen grain core-shell composite materials were prepared by hydrothermal synthesis under ultrasound irradiation by using rapeseed pollen grains as template. The core of the pollen grain could be removed by calcination at 550°C for 6h and the TiO₂ hollow spheres were consequently obtained. SEM, TG, XRD, FTIR and N₂ adsorption were used to characterize the TiO₂/pollen grain core-shell composites and the hollow titania spheres. The results indicate that the ultrasound irradiation helps the dispersion of TiO₂ precursor on the pollen grains' surface uniformly and the suitable amount of tetrabutyl titanate is 6.6g/g pollen, the proper temperature for the hydrothermal synthesis is 105°C. The final TiO₂ hollow spheres with pure anatase phase, have narrow mesopore-size distribution, with an average pore radius of 1.9 nm and BET surface area of 26.76m²·g^-1.