Fabrication of hollow coupled-layered ZnO microstructures using zinc glycerolate precursors

Abstract

Hollow hamburger-like and other coupled-layered ZnO microstructures have been fabricated by a facile solvothermal process using the mixture of water and alcohol as solvents. The volume ratios of water/glycerol play an important role for the morphologies of the microstructures. In the case of a volume ratio of 1/2, the hamburger-like ZnO microstructures are created by employing zinc glycerolate (C₃H₆O₃Zn) as a sacrificial template. A possible formation process from precursor C₃H₆O₃Zn to ZnO is proposed by arresting a series of intermediate phases and the formation mechanism of the microstructures is proposed accordingly. The volume ratios of water/glycerol, such as 1/10, 1/6, 1/4, 1/2 and 1/1, were adjusted to create microstructures with various morphologies. The results indicated that the morphologies of the resulting samples changed from quasi-rhombic C₃H₆O₃Zn plates to various coupled-layered ZnO microstructures, suggesting that water is responsible for the formation of coupled-layered structures. In addition, investigations into the formation of ZnO microstructures in mixtures of water and various alcohols, including water/ethanol, water/isopropyl alcohol, water/n-butyl alcohol, water/ethylene glycol and water/glycerol, reveal that alcohols are crucial for control of the morphologies of the microstructures. The multi-hydroxyl alcohols, e.g. ethylene glycol and glycerol, favour the formation of hollow structures compared with the case of single-hydroxyl alcohols.