Synthesis of ZnO microstructures in glycerol/water solution

Abstract Zinc oxide (ZnO) microrods with high aspect ratio and microstructures with flowerlike morphologies have been synthesized successfully in a glycerol/water reaction system by a simple solvothermal method without adding any surfactants or templates at 180 °C. Experimental results indicated that the flowerlike ZnO microstructures were transformed into rodlike ones with increasing amounts of zinc acetate dihydrate (Zn(Ac) 2 ·2H 2 O) and sodium hydroxide (NaOH) because of the rapid nucleation and growth, indicating that the concentration of reactants is the key to control the morphologies of ZnO samples. In contrast, double-columned and double-hemisphered ZnO microstructures were fabricated using similar solvothermal conditions without adding NaOH by adjusting the proportion of glycerol and water, for these crystallites were generated mainly by esterification between Zn(Ac) 2 ·2H 2 O and glycerol. Time-dependent experiments have also been conducted to explore the evolution of ZnO morphologies. The growth mechanism of as-prepared ZnO structures synthesized in different conditions was discussed.