Facile Fabrication and Superparamagnetism of Silica-Shielded Magnetite Nanoparticles on Carbon Nitride Nanotubes

Authors

  • Jung Woo Lee,

    1. Department of Materials Science & Engineering and NanoCentury KI Korea Advanced Institute of Science and Technology (KAIST) 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Republic of Korea)
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  • Ravindranath Viswan,

    1. Department of Materials Science & Engineering and NanoCentury KI Korea Advanced Institute of Science and Technology (KAIST) 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Republic of Korea)
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  • Yoon Jeong Choi,

    1. Department of Materials Science & Engineering and NanoCentury KI Korea Advanced Institute of Science and Technology (KAIST) 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Republic of Korea)
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  • Yeob Lee,

    1. Department of Materials Science & Engineering and NanoCentury KI Korea Advanced Institute of Science and Technology (KAIST) 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Republic of Korea)
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  • Se Yun Kim,

    1. Department of Materials Science & Engineering and NanoCentury KI Korea Advanced Institute of Science and Technology (KAIST) 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Republic of Korea)
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  • Jaehun Cho,

    1. Quantum Material Research Team Korea Basic Science Institute (KBSI) 113 Gwahangno, Yuseong-gu, Daejeon 305-333 (Republic of Korea)
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  • Younghun Jo,

    1. Quantum Material Research Team Korea Basic Science Institute (KBSI) 113 Gwahangno, Yuseong-gu, Daejeon 305-333 (Republic of Korea)
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  • Jeung Ku Kang

    Corresponding author
    1. Department of Materials Science & Engineering and NanoCentury KI Korea Advanced Institute of Science and Technology (KAIST) 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Republic of Korea)
    • Department of Materials Science & Engineering and NanoCentury KI Korea Advanced Institute of Science and Technology (KAIST) 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Republic of Korea).
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Abstract

Using conventional methods to synthesize magnetic nanoparticles (NPs) with uniform size is a challenging task. Moreover, the degradation of magnetic NPs is an obstacle to practical applications. The fabrication of silica-shielded magnetite NPs on carbon nitride nanotubes (CNNTs) provides a possible route to overcome these problems. While the nitrogen atoms of CNNTs provide selective nucleation sites for NPs of a particular size, the silica layer protects the NPs from oxidation. The morphology and crystal structure of NP–CNNT hybrid material is investigated by transmission electron microscopy (TEM) and X-ray diffraction. In addition, the atomic nature of the N atoms in the NP–CNNT system is studied by near-edge X-ray absorption fine structure spectroscopy (nitrogen K-edge) and calculations of the partial density of states based on first principles. The structure of the silica-shielded NP–CNNT system is analyzed by TEM and energy dispersive X-ray spectroscopy mapping, and their magnetism is measured by vibrating sample and superconducting quantum interference device magnetometers. The silica shielding helps maintain the superparamagnetism of the NPs; without the silica layer, the magnetic properties of NP–CNNT materials significantly degrade over time.

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