ZnO Micro-Nanostructures: Controllable Hydrothermal Synthesis and Photocatalytic Activity

Flower-like, spindle-like and sword-like ZnO micro-nanostructures were synthesized via an ethanolamine-assisted hydrothermal method. The morphology and structure of as-prepared ZnO products were characterized by XRD, SEM, low temperature nitrogen adsorption-desorption(BET surface area), photoluminescence (PL) and Raman spectroscopy. The effect of n(zn2+)/n(OH-) ratio on the morphology of ZnO products was discussed, and the photocatalytic performance was also tested in terms of the organic dye methylene blue degradation. The results demonstrate that all the prepared products possess a wurtzite structure. Their morphology and crystallinity can be controlled by adjusting the molar ratio between Zn2+ and OH-. The ethanolamine is an indispensable solvent in the formation of ZnO products. Compared with commercial ZnO, the prepared ZnO products have higher photocatalytic activity. However, there is no correlation between the BET surface area and the photocatalytic activity. The flowerlike ZnO with a minimum surface area exhibits the highest photocatalytic activity, which can be attributed to its lower crystallinity and special flower-like structure.