TY - JOUR
T1 - Synthesis of carbon nano-onions filled with γ-Fe and Gd/GdCl3
T2 - A candidate multifunctional system
AU - Zhang, Lin
AU - Guo, Xilong
AU - He, Yi
AU - Gu, Aiqun
AU - Lei, Li
AU - Guo, Jian
AU - Zhang, Hong
AU - Boi, Filippo
N1 - Publisher Copyright:
© 2023
PY - 2023/8
Y1 - 2023/8
N2 - Stabilization of high-spin high-volume ferromagnetic γ-Fe nanocrystals inside carbon nano-onions (CNOs) has recently attracted an important attention for possible applications in magnetic hyperthermia cancer therapy. Here we report an advanced investigation of the chemical vapour synthesis (CVS) fabrication methodology of the filled CNOs, with focus on 1) the stabilization of the γ-Fe nanocrystals in presence of larger concentration of Cl radicals and 2) the structural functionalization, through simultaneous encapsulation of both ferromagnetic γ-Fe and paramagnetic GdCl3 phases. By employing HRTEM we demonstrate an anomalous structural configuration of the CNOs, involving the coexistence of defect-rich concentrical-like and radially-oriented graphitic layers. XPS and Raman spectroscopy evidence the presence of C–S bond-formation and defect nucleation as key parameters for the growth of the radially-oriented graphitic layers. This unusual structural arrangement of the CNO is found to stabilize the γ-Fe phase at room temperature. We highlight the absence of FCC to BCC structural relaxation within timescales of 8 months from sample-fabrication. XRD, Rietveld refinements, together with magnetometry confirm the presence of a ferromagnetic transition arising below T ∼ 70 K within γ-Fe. This interpretation is further corroborated through extended characterization with ESR spectroscopy. Structural manipulation and functionalization of the CNOs is demonstrated by including tris(tetramethyl-cyclopentadienyl)gadolinium(III) as a precursor in the pyrolysis experiments. The functionalized CNO (filled with ferromagnetic γ-Fe/Fe3C and paramagnetic Gd/GdCl3) can be visualized as a multifunctional-container and a candidate for magnetic-hyperthermia-cancer-therapy and MRI contrast applications.
AB - Stabilization of high-spin high-volume ferromagnetic γ-Fe nanocrystals inside carbon nano-onions (CNOs) has recently attracted an important attention for possible applications in magnetic hyperthermia cancer therapy. Here we report an advanced investigation of the chemical vapour synthesis (CVS) fabrication methodology of the filled CNOs, with focus on 1) the stabilization of the γ-Fe nanocrystals in presence of larger concentration of Cl radicals and 2) the structural functionalization, through simultaneous encapsulation of both ferromagnetic γ-Fe and paramagnetic GdCl3 phases. By employing HRTEM we demonstrate an anomalous structural configuration of the CNOs, involving the coexistence of defect-rich concentrical-like and radially-oriented graphitic layers. XPS and Raman spectroscopy evidence the presence of C–S bond-formation and defect nucleation as key parameters for the growth of the radially-oriented graphitic layers. This unusual structural arrangement of the CNO is found to stabilize the γ-Fe phase at room temperature. We highlight the absence of FCC to BCC structural relaxation within timescales of 8 months from sample-fabrication. XRD, Rietveld refinements, together with magnetometry confirm the presence of a ferromagnetic transition arising below T ∼ 70 K within γ-Fe. This interpretation is further corroborated through extended characterization with ESR spectroscopy. Structural manipulation and functionalization of the CNOs is demonstrated by including tris(tetramethyl-cyclopentadienyl)gadolinium(III) as a precursor in the pyrolysis experiments. The functionalized CNO (filled with ferromagnetic γ-Fe/Fe3C and paramagnetic Gd/GdCl3) can be visualized as a multifunctional-container and a candidate for magnetic-hyperthermia-cancer-therapy and MRI contrast applications.
KW - Carbon nano-onions
KW - Gamma-Fe
KW - Magnetic-hyperthermia
KW - Multifunctional-systems
UR - http://www.scopus.com/inward/record.url?scp=85163513030&partnerID=8YFLogxK
U2 - 10.1016/j.diamond.2023.110158
DO - 10.1016/j.diamond.2023.110158
M3 - Article
AN - SCOPUS:85163513030
SN - 0925-9635
VL - 137
JO - Diamond and Related Materials
JF - Diamond and Related Materials
M1 - 110158
ER -