Monodisperse anatase titania microspheres with high-thermal stability and large pore size (∼80 nm) as efficient photocatalysts

To fabricate an effective antibacterial coating on the surfaces of diverse sanitary ceramic utensils, efficient titania photocatalysts with integrated features including high temperature anatase phase stability (>800 °C), excellent particle mobility for the formation of uniform thin coatings, high crystallinity and narrow particle size distribution are desirable. In this study, monodisperse dopant-free titania microspheres were synthesized with large pore size (∼80 nm) that remain anatase even after calcination at 900 °C. These titania microspheres were fabricated via a facile solvothermal treatment of amorphous spheres in the presence of 4.5 wt% ammonia solution and consisted of well-crystallized and faceted anatase nanocrystals with a uniform size of 24 nm. The anatase nanocrystals with high crystallinity and narrow crystal size distribution are responsible for their high temperature stability. The resulting anatase titania microspheres exhibited enhanced photocatalytic performance even after calcination at high temperature due to the retention of the anatase phase and the enhanced crystallinity. Such monodisperse anatase microspheres have potential to be applied as smart coating materials for antibacterial and self-cleaning applications.