Microstructural modification of hollow TiO2 nanospheres and their photocatalytic performance

The microstructure of photocatalysts plays a key role in enhancing their photocatalytic performance. Herein, resorcinol/formaldehyde (RF) polymer resin was prepared using the extended Stöber process and used for hard templates. Hollow TiO 2 spheres (HTS) were synthesized via hydrolysis of a versatile kinetics-controlled coating and carbonization method. The physicochemical properties of as-prepared catalysts were characterized. The pure RF template had a uniform diameter of ~450 nm. By adjusting the ammonia dosage from 0.1 to 0.35 mL, monodisperse RF@TiO 2 spheres were obtained with a porous TiO 2 shell of ~25–160 nm in thickness. The concentration of ammonia had a significant effect on the micromorphology, and hence, the photocatalytic properties of the HTS. The Brunauer-Emmett-Teller surface area and pore volume were ~30 m 2 /g and 0.082 cm 3 /g, respectively. The intrinsically high conductivity of the HTS microspheres and their high surface area resulting from this robust hollow structure was beneficial for photocatalytic performance toward phenol decomposition.