Facile preparation of porous ZnO microflowers with large surface area

ZnO microflowers (MFs) assembled by many porous nanosheets were prepared through an initial hydrothermal reaction with an extra annealing treatment at 300 °C. The samples were characterized by XRD, SEM, and TEM techniques, as well as the N2 adsorption–desorption test. The results indicated that the ZnO MFs possessed a size of about 6 µm and exhibited a large surface area of 58.6 m2/g, an average pore size of 14.1 nm with size distribution at 15.1 nm. The hydrothermal temperature was found to play an important role in determining the shape and size of ZnO products. Such ZnO MFs with porous structure and huge surface area may have application potential in the fields of gas sensors, photo-catalysis, electrochemical energy storage, and so on. The present synthetic method is simple and cost-effective, and can be extended to the preparation of other metal oxides with controlled structures.