Effect of Acetate ion during Aging on the Morphology of Zinc Oxide Obtained from Zinc Hydroxide Chloride and Zinc Hydroxide Acetate

Abstract

Zinc oxide, ZnO, was synthesized using layered zinc hydroxide chloride, ZHC, and acetate, ZHA, as precursors. In the first experiment, ZHC and ZHA were hydrothermally synthesized in deionized water. Due to the different precursors, rod-like ZnO particles of 1 μm in length were synthesized by aging ZHC, while rod-like zinc oxide particles of 4 μm in length were synthesized by aging ZHA. In the second experiment, a two-step aging was performed. ZHC and ZHA were aged in a zinc acetate aqueous solution before being aged in deionized water. After the first aging, a mixture of ZHA and ZnO was obtained in both samples. Because of the acetate ions in the solution, coin-shaped ZnO particles with diameters of 1 μm for the ZHC sample and hexagonal plate-like ZnO particles with diameters of 4 μm for the ZHA sample were obtained. Acetate ions form zinc complexes and inhibit the growth of ZnO in the c-axis direction for rod-like growth. Therefore, coin shaped ZnO was obtained. After the second aging, ZnOs with the same shape as in the first aging were obtained in a single phase. From these results, we conclude that the particle size of ZnO can be controlled by the choice of precursor and the particle shape of ZnO can be controlled by the choice of aqueous solution.