Synthesis of hierarchical porous ZnO/Ag microspheres with enhanced photocatalytic activity

Hierarchical porous zinc oxide (ZnO)/silver (Ag) microspheres were prepared by two-step method. The porous ZnO microspheres were prepared firstly, and then Ag nanoparticles were evenly anchored on the surface of ZnO microspheres by Sn2+ activation method. The results show that ZnO is wurtzite phase, and Ag particles are only coated on the surface of ZnO microspheres. Compared with pure ZnO, there are two obvious absorption peaks of Ag-doped ZnO, which corresponds to the ultraviolet absorption peak of ZnO and the plasma resonance absorption peak of Ag, respectively. The intensities of photoluminescence peak of ZnO/Ag microspheres are significantly lower than that of pure ZnO. Moreover, ZnO/Ag microspheres show higher photocatalytic activity than ZnO, which may be attributed to the existence of highly dispersed Ag.