Single Gold Nanoparticles Encapsulated in Monodispersed Regular Spheres of Mesostructured Silica Produced by Pseudomorphic Transformation

Monodispersed, uniform, gold encapsulated−mesoporous silica nanocomposites of 100−350 nm diameter with a centered metal core at about 15 or 30 nm and high gold occupancy are prepared by pseudomorphic transformation of preformed gold−silica nanospheres. The characterization by X-ray powder diffraction, transmission electron microscopy, 29 Si and 13 C magic angle spinning NMR, and N 2 adsorption isotherms indicates that these materials present the same morphology and particle size distribution of the parent amorphous silica but with an ordered mesoporous shell of complex wormhole-like pore structure and specific surface area of about 1000 m 2 g -1 . This method is particularly advantageous for both stabilizing gold nanoparticles and tailoring structural and textural parameters of the outer shell, thus, offering an exceptional support for particle functionalization.