Facile synthesis of zinc oxide crystal and insight into its morphological effect on organic dye photodegradation in water

Metal oxides particularly for zinc oxide (ZnO) particles are well-known to exhibit photocatalytic activities. However, the specific morphology and superstructure of nanomaterials can significantly influence this capacity. Here, it is shown that different crystalline structures of ZnO particles are provided by a facile one-step wet-chemical route. One possible formation mechanism has been elucidated for the fabrication of distinct metal oxide samples including flower-like, sphere-like and leaf-like ZnO under different synthesis conditions. It is also found that the photodegradative performance for organic dye is directly correlated to the morphological properties of these as-prepared catalysts; the higher the active surface area the better is the photocatalytic efficiency. Not only can ZnO structure with abundant mesoporous aggregated by leaf-shape arrays lead to more methylene blue immobilization, but also generate more photoinduced electrons and holes on the crystalline surface. The results also illustrate that the morphology-dependent catalytic performance can be further improved combining with other optimized photodegradative conditions (e.g. pH, illumination mode). The present study can lead to new metal oxide with high-performance important for photocatalytic and environmental applications.