A controllable hydrothermal fabrication of hierarchical ZnO microstructures and its gas sensing properties
In this paper, rod-flower like ZnO hierarchical microstructures with high uniformity are synthesized from the thermal decomposition of Zn(NH3)42+ precursors, which are prepared via a surfactant-assisted hydrothermal process. The as-synthesized hierarchical ZnO microstructure is assembled from columnar nanorods, and the measured length to diameter ratio of the nanorod is about 20. The morphology of the hierarchical ZnO microstructure can be tailored by varying hydrothermal conditions, e.g., hydrothermal temperature, reaction time, concentration of Zn2+ and zinc salts. Moreover, based on the experimental results, the possible reaction mechanism for the growth of the as-synthesized hierarchical ZnO microstructures is also discussed in detail,and the Zn2+ concentration was found to be a crucial role in the formation and nucleation of the rod flower-like microstructures. In addition, the gas sensing test demonstrates that the sensors based on hierarchical ZnO microstructures exhibits excellent gas sensing properties due to its unique architecture.