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 nanoparticle s have been prepared by the reaction of SnCl4 or SiCl4 with Mg2Sn in ethyle ne glycol dimethyl ether (glyme) and subsequently with n-C4H9Li Sn/SiO2 cor e/shell nanoparticles are produced from the reaction of Mg2Sn with SiCl4 an d subsequent reaction with H2O2 Fourier transform Infrared (FTIR) spectra a re 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 n anoparticles. High-resolution transmission electron microscope (HRTEM) conf irms that the core part of Sn/n-butyl and Sn/Si- n-butyl nanoparticles is c onsistent with the tetragonal structure of tin, exhibiting lattice fringes of the {200} crystal plane (2.92 Angstrom). The FTIR spectrum of Sn/SiO2 co nfirms the evidence of silica capping and selected area electron diffractio n (SAED) is consistent with an amorphous shell (SiO2) and crystalline Sn co re. Solid-state nuclear magnetic resonance (NMR) spectra and X-ray powder d iffraction (XRD) pattern provide supporting evidence for the tetragonal str ucture of beta-tin as the core part of Sn/SiO2 nanoparticles. The typical s ize distribution of Sn/n-butyl, Sn/Si-n-butyl, and Sn/SiO2 nanoparticles (d iameter) range from 7 to 15 nm derived from TEM micrographs. The average ra dius ratio (Rr) value, (radius of SiO2/radius of Sn) for Sn/SiO2 derived fr om 24 individual nanoparticles in TEM images is 0.17 (0.02).