Glycol Assisted Hydrothermal Synthesis Of Oxide Nanostructures And Characterization

Nanostructures with various morphologies have attracted great interests due to their significant potential applications. One-dimensional nanomaterials have received intensive interests due to their novel physical, chemical, and biological properties as well as the potential applications in nanodevices. Comparing to other methods, hydrothermal method has been widely employed to prepare one-dimensional nanomaterials due to its advantages of low temperature, simplicity, and large-scale production.In this paper, the novel Ethylene Glycol (EG) assisted hydrothermal method is used to prepare the novel dendrite-like CuO and FeOOH nanostructures successfully. The main results are the following:The dendrite-like CuO and flower-like Cu₂O nanostructures have been synthesized by EG-assisted hydrothermal route. When no EG in the hydrothermal solution, flake-like CuO nanostructures is obtained. The results of the experiments indicate that EG is critical to the preparation of the dendrite-like nanostructures and at the same time it is found that EG is an assistor only when pH value of the hydrothermal solution is within an appropriate range. Moreover, EG is not only an assistor but also has the ability of reducing under the certain pH value. If low quantity of EG is added into the solution, the dendrite-like nanostructures can be prepared, but when with high quantity of EG addition, flower-like and cubic Cu₂O nanostructures are achieved. Based on that, the effects of reaction conditions including the quantity of EG, pH value, reaction temperature and the source concentrations on the morphology and phase of the resulting products are further studied, at the same time, the mechanism of such dendrite-like nanostructures is preliminary presented. Such results will probably be helpful to the controllable fabrication of various nanostructures.Similarly, during the preparation of FeOOH nanostructures, when no EG theflake-like FeOOH nanostructures are synthesized, otherwise, if EG is introduced into the hydrothermal solution, dendrite-like FeOOH can also be fabricated. After the annealing of FeOOH, the corresponding Fe₂O₃ nanostructures are obtained. When the pH value is low in the hydrothermal solution, the product synthesized is Fe₂O₃ nanoparticles. Further investigation shows that the higher the resource concentration is, the larger the nanoparticles are.The UV-vis absorption spectra of the Fe₂O₃ nanostructures with various morphologies show that with the size decrease of the nanoparticles there is blue-shift to the absorption peaks. The magnetization curves of the Fe₂O₃ nanostructures with various morphologies indicate that the morphology has great effects on the magnetic properties of the Fe₂O₃ nanostructures. With the size increase of the Fe₂O₃ nanostructures, the coercive force and residual magnetism are reduced, but the saturation magnetization increases.