Alkali-dependent synthesis of flower-like ZnO structures with enhanced photocatalytic activity via a facile hydrothermal method

Flower-like ZnO structures with high photocatalytic performance were successfully synthesized via a facile hydrothermal method. Alkaline environment played a critical role during the morphological transformation. When the molar ratio of Zn(CH3COO)2·2H2O to NaOH was set as 1:8 in the presence of triethanolamine (TEA), and the molar ratio of Zn2+ to TEA was 1:9, the flower-like ZnO product was produced. The hexagonal sphere-like, oblate-like, and hexagonal biprism-like samples were also obtained by adjusting the molar ratio of Zn2+ to NaOH as 1:2, 1:5 and 1:12 with the presence of invariable amount of TEA, respectively. The prepared ZnO products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) surface area. Photodegradation experiments of the samples were carried out by choosing Methylene Blue (MB) as a model target under UV irradiation with homemade photocatalytic apparatus. Among these products, flower-shaped samples exhibited the highest photocatalytic activity.

► Flower-like ZnO structures are prepared by a facile hydrothermal method. ► Alkaline environments are responsible for the morphological transition. ► Flower-shaped ZnO samples exhibit the highest photocatalytic activity. ► The growth mechanism and photodegradation process are proposed.