Preparation and characteration of mesoporous silica supported Pt and Au nanoparticles by microwave synthesis

• Main Authors: Wei-ChunKao, 高維駿
• Other Authors: Weng-Sing Hwang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/56319750128683214569

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 98 === The study of mesoporous silica supported metal nanoparticles included three parts. In the first part, highly ordered mesoporous silicas have been synthesized by the use of poly-(alkylene oxide) block copolymers. The crystal structure、porous structure and thermal properties of mesoporous silicas and calcined mesoporous silicas were studied by Small Angle X-Ray Scattering (SAXS)、N2 adsorption/desorption measurement and Thermal Analyzers/Mass spectrometer (TG/DTA). In the second part, the surface of Mesoporous silica functionalized with amine group prior to addition of APTMS by post-synthesis. The samples were studied by High Resolution Fourier Transform Infrared Spectroscopy (HRFTIR) and the effect of APTMS concentration on the crystal structure and porous structure were also studied. In the third part, the Pt nanoparticles and Au nanoparticles integrate with mesoporous silica by chelating agent assisted with microwave synthesis. The effects of APTMS concentration and chelating agent on reducing metal nanoparticles were also studied. The surface morphology of mesoporous silicas after microwave synthesis and the crystal structure of noble nanopartice were studied by High Resolution Transmission Electron Microscopy (HRTEM) and x-Ray Diffraction (XRD). In the first part, the SAXS showed that the as-synthesis mesoporous silicas had similar crystal structure to calcined mesoporous silicas. In he second part, the results showed that the reaction of surface mondification did not affect the crystal structure of mesoporous silica which means the mesoporous silica had chemical stability. The N2 adsorption/desorption measurement showed that the surface mondification of as-synthesis sample was similar to calcined sample. In the last part, the HRTEM showed the average size of Pt nanoparticles and Au nanoparticles were about 0.61 nm and 1.74 nm. The Pt nanoparticles were extremelly small in size without the quantum size effect because the amine group could stable the Pt nanoparticles. Also, the Pt particles were highly dispersed by amine group assisted. When the weight ratio of mesoporous silicas (calcined mesoporous silicas) and APTMS were 1:1 and 1:0.6, the Au nanopartilce were highly dispersed. Meanwhile, the Au nanoparticles clustered, when the weight ratio reduced to 1:0.2.