Hollow mesoporous TiO2 spheres (THs) were prepared via template-directed deposition ofTiO2 nanopar-ticles on the surface of carbon spheres.The carbon spheres were used as hard templates.Their diameters were controlled by pH adjustment prior to a hydrothermal process.Physical properties,such as crystallinity,optical characteristics,microstructure and surface morphology of the samples were char-acterized.The results showed that the diameter of the carbon template could be well controlled in the range of 397-729 n m by adjusting the initial pH value of the dextrose solution from 3 to 10.Hollow TiO2 spheres with average diameters ranging from 171 to 668 nm and shell thicknesses ranging from 28 to 47 nm formed by heat treatment at 450 ℃.The photocatalytic performance of hollow TiO2 spheres and TiO2 nanoparticles was examined under UVA irradiation using a methyl orange aqueous solution as an artificial dye.The study revealed that the THs synthesized using a dextrose solution at pH 7 had a higher photocatalytic activity compared to other samples since it had the lowest shell thickness and the proper optical band gap of 3.12 eV with the longest lifetime of electron-hole pair separation.