Facile synthesis of near-monodisperse Ag@Ni core–shell nanoparticles and their application for catalytic generation of hydrogen

• Published in: Nanotechnology 2011-05, Vol.22 (19), p.195604-195604
• Main Authors: Guo, Huizhang, Chen, Yuanzhi, Chen, Xiaozhen, Wen, Ruitao, Yue, Guang-Hui, Peng, Dong-Liang
• Format: Article
• Language: English
• Subjects: Amines - chemistry; Catalysis; Hydrogen - chemistry; Hydrogen-Ion Concentration; Magnetics; Microscopy, Electron, Transmission - methods; Nanoparticles - chemistry; Nanotechnology - methods; Nickel - chemistry; Silver - chemistry; Solvents - chemistry; Spectrophotometry, Ultraviolet - methods; Surface Plasmon Resonance; Surface-Active Agents - chemistry; X-Ray Diffraction
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/22/19/195604

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.