TEM-Induced Structural Evolution in Amorphous Fe Oxide Nanoparticles

Citations Over TimeTop 10% of 2006 papers

Abstract

Exposure to the high energy electron beam of a TEM changes the morphology of amorphous Fe oxide nanoparticles from solid spheres to hollow shells. Amorphous Fe oxide nanoparticles prepared via high-temperature methods using hexadecylamine and trioctylphosphine oxide surfactants were compared to crystalline gamma-Fe2O3 particles of similar size. Both sets of particles are fully characterized via SQUID magnetometry, X-ray powder diffraction, BET surface analysis, EPR spectroscopy, high-resolution transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). Time-resolved TEM images reveal that the amorphous Fe oxide particles evolve from solid spheres into hollow shells in <2 min, whereas crystalline gamma-Fe2O3 are unaffected by the electron beam. The resulting nanocrystalline Fe oxide shells bear striking resemblance to core-shell nanocrystals, but are a result of a morphology change attributed to restructuring of particle voids and defects induced by quasi-melting in the TEM. These results thus imply that caution is necessary when using TEM to analyze nanoparticle core-shell and heterostructured nanoparticles.

Related Papers

• → Molten salt synthesis of single-crystal Co3O4 nanorods(2006)48 cited
• → Synthesis and characterization of single-crystal MnV2O6 nanobelts(2006)32 cited
• → Synthesis of β-Ga2O3 nanorods(2000)46 cited
• → HRTEM Observation of Rod-Shape Precipitates in Al-Mg-Si-Ag Alloy Aged at 523 K(2007)4 cited
• → Zeolite structure determination using electron crystallography(2008)3 cited