Synthesis and characterization of Sn/R, Sn/Si-R, and Sn/SiO2 core/shell nanoparticles

Nanometer-sized tin, Sn/R, and Sn/Si-R (R = n-C4H9) core/shell nanoparticles have been prepared by the reaction of SnCl4 or SiCl4 with Mg2Sn in ethylene glycol dimethyl ether (glyme) and subsequently with n-C4H9Li Sn/SiO2 core/shell nanoparticles are produced from the reaction of Mg2Sn with SiCl4 and subsequent reaction with H2O2 Fourier transform Infrared (FTIR) spectra are consistent with n-butyl surface termination for the n-butyl-capped tin (Sn/n-butyl) and the silicon-n-butyl capped tin (Sn/Si-n-butyl) core/shell nanoparticles. High-resolution transmission electron microscope (HRTEM) confirms that the core part of Sn/n-butyl and Sn/Si- n-butyl nanoparticles is consistent with the tetragonal structure of tin, exhibiting lattice fringes of the {200} crystal plane (2.92 Angstrom). The FTIR spectrum of Sn/SiO2 confirms the evidence of silica capping and selected area electron diffraction (SAED) is consistent with an amorphous shell (SiO2) and crystalline Sn core. Solid-state nuclear magnetic resonance (NMR) spectra and X-ray powder diffraction (XRD) pattern provide supporting evidence for the tetragonal structure of beta-tin as the core part of Sn/SiO2 nanoparticles. The typical size distribution of Sn/n-butyl, Sn/Si-n-butyl, and Sn/SiO2 nanoparticles (diameter) range from 7 to 15 nm derived from TEM micrographs. The average radius ratio (Rr) value, (radius of SiO2/radius of Sn) for Sn/SiO2 derived from 24 individual nanoparticles in TEM images is 0.17 (0.02).