Carbon Nanotubes
1. Boron nitride nanotubes: demonstrated that NEXAFS is a very effective technique at (a) identifying the phases of boron nitride nanotubes with the potential of distinguishing between hexagonal BN and cubic BN, and (b) monitoring the presence of defects and degree of crystallinity in nanoscale samples. Specifically, a prepared sample of boron nitride nanotubes was characterized by NEXAFS with our results showing that the sample consisted of hexagonal BN tubes that were highly crystalline and sp2-hybridized.
Ref.: Phys. Chem. Chem. Phys., v.8, 5038 (2006).
2. Iron-containing nanostructures: probed the electronic structure and chemistry of iron-based metal oxide nanostructured (FeMONS) materials including BiFeO3, Bi2Fe4O9, α-Fe2O3, γ-Fe2O3, and Fe/Fe3O4. Correlations of the electronic structure and structural chemistry of these intriguing nanomaterials were presented, ranging from the nano to the bulk scale. Specifically, variations in the shape, position, and intensity of the O K-edge and Fe L-edge NEXAFS spectra were analyzed in terms of electronic structure and surface chemistry of the FeMONS materials as compared with that of the bulk. We hypothesized that surface imperfection and surface strain anisotropies in nanoparticles induce distortion and site inequivalency of the oxygen Oh sites around the Fe ion located close to the surface, resulting in an increase in the degree of multiplicity as well as in non-stoichiometric effects in FeMONS materials.
Ref.: J. Phys. Chem. C, v.112, 10359 (2008).
