Structural and magnetic properties of mesoporous SiO2 nanoparticles impregnated with iron oxide or cobalt-iron oxide nanocrystals (Articolo in rivista)

Type
Label
  • Structural and magnetic properties of mesoporous SiO2 nanoparticles impregnated with iron oxide or cobalt-iron oxide nanocrystals (Articolo in rivista) (literal)
Anno
  • 2012-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1039/c2jm32314a (literal)
Alternative label
  • Parma, Alvise; Freris, Isidora; Riello, Pietro; Cristofori, Davide; de Julian Fernandez, Cesar ; Amendola, Vincenzo; Meneghetti, Moreno; Benedetti, Alvise (2012)
    Structural and magnetic properties of mesoporous SiO2 nanoparticles impregnated with iron oxide or cobalt-iron oxide nanocrystals
    in Journal of materials chemistry (Print)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Parma, Alvise; Freris, Isidora; Riello, Pietro; Cristofori, Davide; de Julian Fernandez, Cesar ; Amendola, Vincenzo; Meneghetti, Moreno; Benedetti, Alvise (literal)
Pagina inizio
  • 19276 (literal)
Pagina fine
  • 19288 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 22 (literal)
Rivista
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali
  • 13 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo
  • 36 (literal)
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Universita Ca Foscari Venezia; INSTM; Consiglio Nazionale delle Ricerche (CNR); University of Florence; University of Padua (literal)
Titolo
  • Structural and magnetic properties of mesoporous SiO2 nanoparticles impregnated with iron oxide or cobalt-iron oxide nanocrystals (literal)
Abstract
  • Magnetic nanocomposites of FeOx@SiO2 and CoFe2O4@SiO2 were prepared via a wet-impregnation route using mesoporous silica nanoparticles as a support matrix. The small pores in the matrix were exploited as nanocavities for controlled growth of the embedded oxide phase, initially examined by introducing different wt% loadings of FeOx in four different samples and sequentially treating them under oxidising and reducing conditions. Comparative examination of the morphological and structural properties of the FeOx@SiO2 compositions shows that a 17 wt% (nominal) loading of the oxide phase, a mixture of Fe3O4 (magnetite) and gamma-Fe2O3 (maghemite), is fully embedded within the pores. The 60-70 nm dimensions of the SiO2 nanoparticles are visible in TEM micrographs which reveal a spheroidal shape. TEM also shows a ca. 3 nm size for the crystalline oxide particles embedded within, which agrees with the pore sizes estimated through porosimetric analysis. The measurements for field-cooled (FC), zero-field-cooled (ZFC) magnetizations, and hysteresis loops in the temperature range of 3 K to 300 K reveal that an enhancement in the density of magnetization is obtained for the 17 wt% FeOx@SiO2 sample following reductive thermal treatment. A CoFe2O4@SiO2 nanocomposite prepared with a nominal 14 wt% oxide shows comparable structure and morphology to the 17 wt% FeOx@SiO2 sample, yet superior magnetic properties. The higher density of magnetization in CoFe2O4@SiO2 is attributed to its 40% content of magnetic material in the crystalline phase, versus 6-8% in FeOx@SiO2. Efficient surface functionalisation with APTES, monitored by DRIFT-IR, implies that the magnetic nanocomposites could be used in bio-labelling applications. Data derived from Raman spectroscopy, N-2 adsorption/desorption measurements, and TGA are also used to characterise the nanocomposite materials. (literal)
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