Synthesis and characterization of platinum and iron nanoparticles

Abstract

The purpose of this project was to achieve shape controlled synthesis of platinum nanoparticles and understand the growth mechanism of the platinum nanoparticles formed. This project was also aiming to synthesize iron/iron oxides core/shell nanoparticles for biomedical applications. In the synthesis of platinum nanoparticles, a platinum precursor was decomposed in a hydrogen atmosphere in presence of surfactant. The resulting products were characterized by high resolution transmission electron microscope (HRTEM) and selected area electron diffraction (SAED). By controlling the precursor concentration, polydispersed platinum nanocubes with growth of {1,0,0} facets and highly monodispersed platinum nanocubes were formed. Monodispersed platinum nanocubes are formed in a two step growth mechanism with initial growth of the {1,1,1} facets followed by secondary growth filling the {1,0,0} facets. The particle monodispersity facilitates the formation of long range arrays of nanocubes. Changing in the reaction temperature resulted in the formation of platinum tripods, octapods and multipods. Particle morphologies could be understood by consideration of the nucleation and selected growth of the particles on different facets. Ferromagnetic iron/iron oxides core/shell nanoparticles were produced through a two step heating process with a decomposition of iron precursor in Fischer-Porter bottle. The products were characterized by HRTEM, SAED and vibrating sample magnetometer (VSM). The particles formed have a structure of 2 - 3 nm iron oxide shell and 15 - 20 nm iron core. The shell has been found to be crystalline and could protect the particles from deep oxidation. The particles were ferromagnetic at room temperature with a magnetic moment density over 130 emu/g.