Template-free Fabrication of ZnS/TiO2 Photocatalyst with Macrochannels

Constructing a porous structure in photocatalysts is an effective strategy for improving the photocatalytic activity because of its enhanced molecule transfer capability and light capturing efficiency. In this work, a hierarchical macro-/mesoporous ZnS/TiO2 composite with macrochannels was successfully synthesized without using templates by the simple dropwise addition of an ethanol solution of tetrabutyl titanate and zinc acetate into a sodium sulfide aqueous solution, which was then calcined at 450 degrees C. Compared with pure TiO2, the ordered porous ZnS/TiO2 composite exhibited an enhanced photocatalytic activity on methylene blue removal under UV-light irradiation. The results indicate that the macro-/mesoporous structure, the large specific surface area, and the heterostructure combination between ZnS and TiO2 play a synergistic effect on the enhanced photocatalytic activity via improving the light absorption and the diffusion of organic molecules, providing more reactive sites for the photocatalytic reaction and improving the separation of photogenerated electron-hole pairs, respectively. Radical trapping experiments demonstrated that holes (h(+)) and superoxide anion radicals (O-2(-)) play an important role in the photocatalytic oxidation process.