title: Facile synthesis of near-monodisperse Ag@Ni core-shell nanoparticles and their application for catalytic generation of hydrogen.
abstract: Magnetically recyclable Ag-Ni core-shell nanoparticles have been fabricated via a simple one-pot synthetic route using oleylamine both as solvent and reducing agent and triphenylphosphine as a surfactant. As characterized by transmission electron microscopy (TEM), the as-synthesized Ag-Ni core-shell nanoparticles exhibit a very narrow size distribution with a typical size of 14.9 ± 1.2 nm and a tunable shell thickness. UV-vis absorption spectroscopy study shows that the formation of a Ni shell on Ag core can damp the surface plasmon resonance (SPR) of the Ag core and lead to a red-shifted SPR absorption peak. Magnetic measurement indicates that all the as-synthesized Ag-Ni core-shell nanoparticles are superparamagnetic at room temperature, and their blocking temperatures can be controlled by modulating the shell thickness. The as-synthesized Ag-Ni core-shell nanoparticles exhibit excellent catalytic properties for the generation of H(2) from dehydrogenation of sodium borohydride in aqueous solutions. The hydrogen generation rate of Ag-Ni core-shell nanoparticles is found to be much higher than that of Ag and Ni nanoparticles of a similar size, and the calculated activation energy for hydrogen generation is lower than that of many bimetallic catalysts. The strategy employed here can also be extended to other noble-magnetic metal systems.
authors: Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen, People's Republic of China.
authors: Huizhang
authors: H
authors: Guo
authors: Yuanzhi
authors: Y
authors: Chen
authors: Xiaozhen
authors: X
authors: Chen
authors: Ruitao
authors: R
authors: Wen
authors: Guang-Hui
authors: GH
authors: Yue
authors: Dong-Liang
authors: DL
authors: Peng
mesh_terms: D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008280:Magnetics; D046529:Microscopy, Electron, Transmission / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D009532:Nickel / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D020349:Surface Plasmon Resonance; D013501:Surface-Active Agents / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000588:Amines; D012997:Solvents; D013501:Surface-Active Agents; D012834:Silver; D009532:Nickel; D006859:Hydrogen; C008703:oleylamine