Preparation and Photocatalytic Property of the Hierarchical Mesoporous ZnO Microspheres

The zinc hydroxide carbonate (ZHC) precursor was synthesized by hydrothermal method in a autoclave using zinc nitrate hexahydrate, urea and tartaric acid as the source materials. Hierarchical porous ZnO microspheres have been successfully synthesized by calcining the microspheric ZHC. The result of scanning electron microscope (SEM) shows that the as-prepared ZnO microspheres with a diameter between 2-4 μm. The microspheres are assembled by numerous porous nanosheets which have the uniform thickness about 10 nm. The hierarchical ZnO microspheres were further charactered by X-ray diffraction (XRD) and transmission electron microscope (TEM), the results clearly show that the ZnO microspheres exhibit a typical wurtzite structure and are well crystallized. Brunauer-Emmett-Teller(BET) confirms that the ZnO microspheres are hierarchical mesoporous structures, the diameter of mesoporous on the nanosheets are in the range of 20-50 nm. The specific surface area of the ZnO microshperes is about 29.8 m/g. The photocatalytic activity of the ZnO microspheres was evaluated by photode-gradation reaction of methylene blue (MB). The results show that the hierarchical porous ZnO microspheres exhibit high photocatalytic activity.