Easy synthesis of highly monodispersed silica@M (M = Ag, Au, Pd, Pt) particles using thiol compounds as a connecting agent

Silica@M (M = Ag, Au, Pd, Pt) particles were prepared by accumulating noble metal nanoparticles on the surface of thiolfunctionalized silica as a substrate, which was accomplished by the strong interaction between noble metal nanoparticles and thiol groups. In the conventional method, the fabrication of metal coated silica spheres by LBL (layer-by-layer) or core-shell synthesis is not efficient due to the complexity of the synthetic method, the low surface coverage of functional groups on the particles, and the low loading capacity of noble metal particles. The synthetic method in this study could overcome these limitations and make possible the simple preparation of the silica@M (M = Ag, Au, Pd, Pt) and hollow Pt metal particles with substantial metallic layers via a self-assembly behavior by a strong interaction between noble metal nanoparticles and thiol groups. Detailed characterizations of the silica@M (M = Ag, Au, Pd, Pt) and hollow Pt metal particles were performed to elucidate the surface and structural properties, the coordination of noble metals, and the crystalline structure of the noble metals on the surface by various analytical methods.