The Effect of Divalent Metal Ions on the Morphology of Zinc Oxide Synthesized from Layered Zinc Hydroxide Acetate

抄録

ZnO was synthesized by using layered zinc hydroxide acetate (ZHA), as a precursor. ZHA was aged in zinc acetate (ZnAc), magnesium acetate (MgAc), and barium acetate (BaAc) aqueous solutions under hydrothermal condition. The effect of divalent metal ions, Zn²⁺, Mg²⁺ and Ba²⁺, on the morphology of ZnO was studied. Results show that thin and thick plate-like and rod-like ZnO particles were synthesized for aging in ZnAc, MgAc and BaAc aqueous solution, respectively. In addition, the length to the c-axis direction became smaller in ZnAc and MgAc solution, and longer in BaAc solution, respectively, by increasing the concentration. Zn²⁺ and Mg²⁺ complexes with hydroxide and acetate ion are stable in aqueous solution. They adsorb on the growth plane instead of the growth unit of ZnO, Zn(OH)₄²⁻, and would inhibit the c-axis direction growth. Thus, ZnO particles with shorter length are obtained. On the other hand, since Ba²⁺ complexes are unstable, Ba²⁺ ions would not affect the morphology of ZnO, and therefore ZnO particles with longer length are obtained. It is concluded that morphology of ZnO, especially the c-axis length, is controlled by selecting metal ions with appropriate complex stability constants.

Fig. 7 SEM images of ZHAs aged at 90°C for 24 h in 150 mL of 1.5, 1.0 and 0.1 mol L⁻¹ ZnAc, MgAc and BaAc aqueous solutions.