Mesoporous SiO₂ yolk shell confined core-satellite Ag nanoparticles: Preparation and catalytic activity

In this work, novel mesoporous SiO₂ yolk-shell confined core-satellite Ag nanoparticles (Ag@mSiO₂) synthesized with a simple route were reported. Firstly, the core/shell Ag@C nanospheres whose carbon shells were doped with Ag nanoparticles, were facilely prepared by using a simple hydrothermal method. After coating with a uniform layer of hybrid SiO₂ in the presence of octadecyltrimethoxysilane (C₁₈TMS), the Ag@C@h-SiO₂ composite nanospheres were obtained. The final calcination removed all the carbon and organic compound and left the yolk shell Ag@mSiO₂ nanosphere, in which an individually large Ag core and many tiny Ag nanoparticles were encapsulated within the mesoporous silica shell. The core-satellite like Ag nanoparticles exhibited excellent catalytic activity in RhB reduction. Benefited from the m-SiO₂ shell with a uniform pore size of 3.5 nm, the bi-mode Ag nanoparticles were very stable, thus the activity of Ag@mSiO₂ could keep as high as 92% after five cycles.