Fabrication and photocatalytic properties of porous ZnO architectures

In this work, a series of porous zinc oxide (ZnO) architectures were prepared by changing the concentration of trisodium citrate by using a green hydrothermal and calcination method, and the photocatalytic performance of the ZnO samples were investigated by using Rhodamine B as degradant under ultraviolet irradiation. The concentration of trisodium citrate had a great influence on the morphology, structure and optical properties of the ZnO samples, which together affected the photocatalytic activity. With the increase of trisodium citrate concentration, the morphology of as-prepared hexagonal wurtzite ZnO changed from flower-like to porous microsphere, and then formed bigger spheres which were more tightly assembled by nanosheets. The higher photocatalytic performance of ZnO microsphere prepared from 1 × 10−3 mol·l−1 trisodium citrate solution was due to the hierarchical pore structure, its better ultraviolet light absorption and higher charge separation. Moreover, the mechanism of the dye photodegradation reaction was discussed.