The Fabrication And Characterization Of Noble Metal High Index Surfaces On The Specific Morphology Of Ag Nanoparticles

Pt nanocrystals with high-index facets(HIFs)exposed has drawn a great deal of attention due to its unique performance,however its application was hindered by its large size,low dispersity,which leads to low utilization rate of precious metal.In this thesis,relatively inexpensive silver nanoparticles were employed as basement for the redox deposition of precious metal Pt in which the arrangement of Pt atoms was tuned by the specific index of Ag nanoparticles so that a kind of Pt loaded Ag nanoparticles with both high dispersity and HIFs of Pt was synthesized and its catalysis performance in CH3OH electrooxidation was investigated.To obtain an appropriate silver nanoparticles basement,3 kinds of Ag nanoparticles,Ag nanocube?Ag nanoplate and Ag nanooctahedra,were synthesized and characterized by UV-vis?XRD?ICP-AES and TEM.Results show that both kinds of Ag nanoparticleswere obtained with excepting morphology,however the Ag nanoplate and Ag nanooctahedra are not capable to be employed as basement due to the low yield,inconvenience in purification and easiness in deformation and the Ag nanocube was elected as basement for synthesis of Pt^Ag.A series of Pt^Ag with different Pt loadings were prepared via redox replacement between the atoms in the surface of Ag nanocube and Na2PtC16(the precursor of Pt)with different surfactants.functional molecules as well as the precusor adding quantity and characterized by UV-vis?XRD?ICP-AES?TEM.Results show that the Pt^Ag concave nanocubes partially coated by Pt atoms with HIFs was prepared successfully and preliminary research indicates that Ag^Pt possessed higher activity in CH3OH electrooxidation.Above exploration indicate that the HIFs could be obtained by depositing Pt onto specific index of Ag nanoparticles.Noble metal nanoparticles with both high utilization rate and HIFs covered could be prepared via this method,which provide a practicable route for synthesis of precious metal nanocrystals covered by HIFs with practical value and is promising in synthesis of other noble metal nanoparticle with HIFs.