A mechanistic study of oleic acid-mediated solvothermal shape controllable preparation of zinc oxide nanostructures

• Cartridge-clip ZnO nanorod arrays have been prepared by wet chemical methods.
• By tailoring the added amount of oleic acid, various ZnO shapes have been prepared.
• Oleic acid acts as multiple roles: capping agent and the reactant.

In the present work, for the first time, we prepared cartridge-clip nanorod arrays by wet chemical method using trioctylamine as the solvent. By changing the addition amount of oleic acid, this structure can be transferred to plates and other irregular structures respectively. TEM, XRD, and thermogravimetric analysis reveals that oleic acid acts as multiple roles: capping agent, ethant for ZnO nanorod arrays, and the reactant to form zinc-oleate complex with zinc acetate. The formation of cartridge-clip nanorod arrays is ascribed to the decomposition temperature difference of zinc acetate with zinc oleate: firstly produced ZnO nanoparticles decomposed by zinc acetate self-assemble into plates as the substrate for the further growth of ZnO generated by zinc oleate. In these processes, prolonged reaction and aged time can result in the dissolution of nanorod arrays to cone and plate structures. In addition, the solvent trioctylamine also plays an important role as chelating reagent in the shape formation process. On the basis of these acknowledges, a nucleation–self-assembly–dissolution mechanism is hereby proposed.

Here, for the first time, cartridge-clip ZnO nanorod arrays have been prepared by wet chemical methods using oleic acid as the capping agent. By tailoring the added amount of oleic acid, various ZnO shapes, such as plates and cones, have been also prepared. It is found that oleic acid acts as multiple roles: capping agent, etchant for nanorod arrays, and the reactant to form zinc-oleate complex with zinc acetate.Figure optionsDownload as PowerPoint slide