Activité: Types de discours ou de présentation › Présentation orale
A simple and very efficient method comprising infrared (IR) irradiation and diazonium chemistry is used to synthesize maghemite nanocrystals decorated multi-wall carbon nanotubes (MWCNTs) with magnetic and electronic properties enhanced nanocomposites. The present method overcomes the problem faced in the last decade for the decoration of carbon nanotubes with maghemite nanoparticles. The hybrid materials are characterized using TEM, XPS, STEM, EDX, PXRD, HRTEM and UV-Vis spectrophotometry. The tricarboxylic aryl diazonium (salts generated in-situ) functionalized, purified MWCNTs followed by the treatment with iron (II) ethylenediammonium sulfate using IR radiation is the key step in homogeneous impregnation of functionalized MWCNTs. Calcining this sample under argon atmosphere at 500 °C results in a controlled maghemite nanocrystals decorated MWCNTs. Homogeneously distributed maghemite nanocrystals (cubic crystal system) on MWCNTs surface are found in the size range of 1-6 nm, with a Gaussian mean diameter of ∼1.9 nm. Methylene blue, a model pollutant is used to illustrate the applications of the present material for the decontamination of pollutants in water. Effective integration of properties of both constituents (MWCNTs and maghemite nanocrystals) in the new nanocomposite with superior characteristics are observed. This method is valid for large-scale preparations. It opens very interesting perspectives in nanotechnological and environmental applications .  Iijima, S. Nature 354, 56 (1991).  Bhakta, A.K.; Detriche, S.; Martis, P.; Mascarenhas, R.J; Delhalle, J.; and Mekhalif, Z. J. Mater. Sci. 52, 9648–9660 (2017).  Martis, P.; Venugopal, B.R.; Seffer, J.-F.; Delhalle, J.; and Mekhalif, Z. Acta Mater. 59, 5040-5047 (2011).  Bhakta, A.K.; Kumari, S.; Hussain S.; Martis, P.; Mascarenhas, R.J.; Delhalle, J.; and Mekhalif, Z. (Submitted for publication).