Synthesis Of Noble Metal Embedded Core/Shell Structured Material And Their Properties

Recent years, noble metal nanomaterials are widely explored due to their excellent properties in catalysis, electronics, optics, biology, etc. However, due to the large specific surface area and surface energy, the noble metal nanoparticles are very likely to aggregate during the synthesis and practical application, losing their properties. To develop much more facile synthetic routes to acquire much more stable noble contained nanocomposites is still the main challenge for the related researchers. In order to prepare new kinds of embedded type core/shell structured material, we have successfully synthesized two different kinds of noble metal embedded core/shell structured material in this essay, and their performance in catalysis have been investigated in detail. The details are as follow:[1] Firstly, we briefly reviewed the general trend of noble metal embedded core/shell structured nanocomposites. Specifically, the core/shell and the unique yolk-shell core/shell nanocomposites, noble metal nanoparticles were overviewed. Moreover, the reported noble metal embedded core/shell nanocomposites were also been summarized.[2] Core/shell nanocomposites β-FeOOH@PDA-Au-PDA with the rod-like 3-FeOOH core and sandwich-like poly(dopamine)-Au-poly(dopamine) (PDA-Au-PDA) shell have been prepared via a facile and reproducible synthetic route. The products prepared in each step showed excellent dispersity and uniformity. The rod-like β-FeOOH cores were prepared through high temperature reflux, and then the sandwich-like PDA-Au-PDA shells were tightly attached to the cores through a layer-by-layer coating method. Experienced from exploring the synthetic method, adjusting the concentration of reactant, particles with controllable core size and total size were successfully obtained. By virtue of its ultra-thin outer layer of PDA and distinct structure,β-FeOOH@PDA-Au-PDA nanocomposites showed excellent catalytic activity and greatly improved recyclability.[3] By combination of sonification-assisted hydrothermal method, a modified Stober method and high temperature calcination, novel mesoporous SiO2 yolk/shell confined core-satellite Ag nanoparticles (Ag@mSiO2) were successfully obtained. The products prepared in each step showed excellent dispersity and uniformity. Meanwhile, a reasonable formation mechanism was proposed. The pore size of mesoporous SiO2 was about 3.5 nm, smaller than the diameter of Ag nanoparticles, effectively helped avoid the loss of Ag nanoparticles and their aggregation. The large yolk-shell space provided reaction zone, and the Ag nanoparticles acted as perfect active site, therefore, when the products were applied in the reduction of RhB, they showed superb catalytic activity and greatly improved recyclability.[4] Fe3O4 nanospheres with high magnetic saturation, uniform particle size, excellent homogeneity were facilely synthesized via solvothermal method. Modified Stober method was utilized to encapsulate the Fe3O4 core with a controllable phenolic resin (RF) shell. Ag nanoparticles with the uniform size smaller than 8 nm loaded on the surface of phenolic resin shell in situ. The uniform Ag nanoparticles could provide possibilities in the applications in catalysis, sterilization. Moreover, the superparamagnetic Fe3O4 core can greatly improve the recyclability of Fe3O4@RF-Ag.