CTAB assisted one-pot hydrothermal synthesis of columnar hexagonal-shaped ZnO crystals

In the current paper, we report the preparation of micron sized hexagonal-shaped ZnO crystals having a stepped columnar structure using a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal synthesis route. ZnAc2·2H2O and KOH were used as the starting materials and zinc oxide crystals were obtained following growth at 120 °C for 5 h. Experimental results showed that the presence of CTAB in the system could vary the shape of the ZnO crystals: some rod-shaped ZnO crystals were prepared from the system without CTAB and stepped hexagonal-shaped ZnO crystals were produced from the system with CTAB. The morphology of the final product could also be influenced by the molar ratio of ZnAc2/KOH in the system. The lower concentration of KOH availed the formation of stepped hexagonal shaped ZnO crystals. Furthermore, many nanorods were obtained when ZnCl2 was used as a zinc ion source, which implied that the counter anion in the system could affect the morphology of the final product. A possible formation process of the ZnO crystals was suggested.