Preparation Of Yolk-shell Structure And Mesoporous Hollow Structure Nanomaterials With Sacrificed Template

With the rapid development of nano-materials, nanoparticles（NPs） with special structure have attracted more and more attentions due to their unique structure. Among many NPs with special structure, yolk-shell and hollow structure NPs, represent two new class of special core-shell structure, have attracted a great deal of attention due to their unique structure, properties and important applications in various fields. In recent years, yolk-shell structure with Au NPs as core and the lanthanide-doped upconversion fluorescent hollow nanomaterials have been a hot research topic due to the important applications in various fields. Herein, we designed a simple synthetic route to synthesize yolk-shell structure with single or multiple Au cores and mesoporous hollow lanthanide doped upconversion fluorescent NPs with controlled morphology. Additionally, a variety of characterization methods were used to test the properties of the obtained NPs, including transmission electron microscope（TEM）, scanning electron microscopy（SEM）, nitrogen adsorption-desorption,X-ray powder diffraction（XRD） and upconversion fluorescence spectrophotometer. The results were as follows:（1） Au@mesoporous SnO₂（Au@mSnO₂） yolk-shell NPs were synthesized with Au@SiO₂ core-shell NPs as templates, and their structure and performance have also been investigated. The results show that the synthesized materials exhibit excellent catalytic performance and high stability towards the reduction of 4-nitrophenol.（2） Monodispersed multi-cores Au@mSnO₂ yolk-shell NPs with multiple Au NPs as cores were synthesized with SiO₂ nanosphere as template. The obtained materials exhibit excellent photocatalytic performance and high stability towards degradation of rhodamine B（RhB） solution.（3） Lanthanide-doped（Ln-doped） Gd₂O₃ and GdF3 upconversion（UC） nanospheres（NSs） and nanoshuttles（NHs） have been fabricated using SiO₂ nanosphere as template by simple treatment with Ln Cl3 solution in the presence of urea. Additionally, a variety of testing methods were used to characterize the properties of the obtained materials. These results indicate that the obtained materials have important potential applications value in biological imaging, drug delivery and so on. Furthermore, the method could be extended to synthesize a series of morphology-controllable rare earth oxides and fluorides doped with lanthanide ions.