Collidal Carbon Sphere Template-based Method To Fabricate Ferrite Hollow Spheres And The Relevant Property Researches

Among various magnetic nanomaterials,magnetic hollow spheres attract especially intense interest due to their excellent properties such as high surface area,and the promising potential applications in microencapsulation,drug delivery and magnetic separation etc. Transition metal ferrites with the molecular formula MFe₂O₄ represent as a class of low-cost but widely used technological magnetic materials.Thus,developing simple and economical method to prepare ferrite hollow structures in significant for fabrication and further practicla application of magnetic nanomaterials.In the present research,a simple strategy using colloidal carbon spheres or Ag@C core-shell microspheres as template formed via a simple one-step process is developed for rational fabrication of a class of ferrite hollow structure.Some obvious advantages may be observed in the methods.1.The abundant-OH and-C=O groups make the Ag@C core-shell colloids easy interact with various metal ions with no need of surface modification.2.The formation of metal nanoparticles and the encapsulation into carbon shell were performed in a"one-step"fashion,avoiding complicated multi-step reaction process including formation of metal nanoparticles and subsequent modification of the interior shell.3.The preparation of metal@C microspheres used water as environmentally benign solvent and glucose as reducing reagent,and no toxic reagents were used.Moreover,during the calcination procedure,the carbon shell of the templates transforms into CO₂,which is environmentally circular gas.The other hand,the layer-by-layer technology provides a convenient and effective way to construct nanocomposite materials.It can easily assemble species with opposite charges to composite bilayers,making the combination of various functional species possible.With the micromation of electronic devices,self-assembled multilayer films containing multifunctional nanocomposites will play important roles in the electronic devices area.We successfully fabricated amino acid-POM nanoparticles functionalized ultrathin PE films via LbL assembly technique.The experimental results indicated that the size of the nanoparticles embedded in films could be tuned by controlling the number of adsorption and precipitation cycle. Electrochemical study showed that amino acid-POM nanoparticles in the multilayer films remaind the excellent electrochemical property of the POMs.