The fabrication of rod-like and hierarchical ZnO nanomaterials by a simple and controllable method

Rod-like and hierarchical ZnO nanomaterials were fabricated via a single-step refluxing route in water–methanol mixed solution without any surfactant or template at low temperature. The as-prepared ZnO nanomaterials were characterized by scanning electronic microscopy, X-ray diffractometry and thermogravimetric analysis. By adjusting reaction temperature, precursor concentration and reaction time, ZnO nanomaterials with different morphologies were synthesized. By keeping the reaction temperature above 90 °C, wurtzite ZnO has been grown. With increasing concentration of Zn2+ ions from 0.03 M, 0.06 M to 0.09 M, the morphology of ZnO changes from long rod to short rod and finally hierarchical structures. The specific surface area of hierarchical ZnO was also investigated, and the results show that the hierarchical ZnO has a larger specific surface area (47.75 m² g−1) than that previous reported.