Microwave-Assisted Rapid Synthesis of ZnO Hexagonal Quasi-Hourglasses

To controllably construct ZnO-base heterostructures, unique ZnO hexagonal quasi-hourglasses have been synthesized by a microwave-assisted hydrothermal approach. The phase purity and the morphologies of as-prepared samples have been determined by using X-ray powder diffractometer, field-emission scanning electron microscopy and transmission electron microscopy. We have rationally discussed the growth and reaction mechanism and revealed the morphological evolution of ZnO hexagonal quasi-hourglasses. Dodecylamine, as well as the initial concentration of zinc source, the reaction temperature and time, play an important part in the synthesis of ZnO hexagonal quasi-hourglasses. Between ZnO and Zn5(OH)8(NO3)2, a reversible reaction seldom reported occurs in a circular manner as the reaction proceeds continuously. The presence of ZnO multipods in the products and the controllable synthesis of half of ZnO hexagonal quasi-hourglass betoken a possibility to synthesize ZnO hierarchical architectures, even ZnO-base heterostructures by using this kind of ZnO building blocks.