Composite Ag-Pt Nanoparticles in Aqueous Solution

It is shown that the saturation of an aqueous solution containing K2PtCl4 with hydrogen in the presence of 6.3 nm silver nanoparticles leads to the reduction of platinum on the silver surface and the formation of Ag/Pt core-shell nanoparticles. The Ag:Pt molar ratio is varied from 9:1 to 1:9 for synthesizing Pt shell layer of different thickness. An apparent shift of Ag surface plasmon band from 405 nm to 230 nm and broadening of one with decrease of Ag:Pt ratio was observed. The TEM images and SAED pattern of Pt@Ag nanoparticles has been obtained. The UV-Vis and TEM data confirms a formation of Ag/Pt core-shell nanoparticles.