One-step synthesis, characterizations and mechanistic study of nanosheets-constructed fluffy ZnO and Ag/ZnO spheres used for Rhodamine B photodegradation

Nanosheets-constructed ZnO spheres with novel three-dimensional (3D) fluffy structure were successfully synthesized by a facile one-step solvothermal method. Each fluffy ZnO sphere possesses a diameter of 2–3 μm, consisting of crossed nanosheets with an average thickness of ∼20 nm. Such special hollow 3D structure makes larger surface area and more active sites exposed during the reaction, facilitating the transportation of reactants and products and increasing the reaction rate. The activity measurement for Rhodamine B photodegradation shows that such fluffy ZnO spheres do possess much higher photocatalytic activity than other commonly reported nanostructured ZnO, such as nanoflowers, nanospiraldisks, nanodumbbells and nanorods. The results of photoluminescence spectra show that the fluffy spheres show much higher electron–hole segregation efficiency than other ZnO materials. Through one-pot synthesis Ag is readily doped on the fluffy spheres and strongly interacts with them, further improving the photocatalytic performance of ZnO. Based on the properties and characterization results, a special growth mechanism for such fluffy ZnO spheres is proposed, and the photocatalytic reaction mechanism is also discussed.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ Nanosheets-constructed fluffy ZnO spheres were successfully synthesized. ▶ The fluffy ZnO is more active than other nano-ZnO for Rhodamine B photodegradation. ▶ Doping Ag on the fluffy ZnO spheres further improves its photocatalytic activity. ▶ A special growth mechanism for such fluffy ZnO spheres is proposed.