Controlled reduction synthesis of yolk-shell magnetic@void@C for electromagnetic wave absorption

https://doi.org/10.1016/j.cej.2020.124149Get rights and content

Highlights

  • Magnetic@void@C composites were fabricated via controlled reduction strategy.

  • Magnetic-carbon absorbers own magnetic loss, dielectric loss and synergistic effect.

  • Strong absorption, broad bandwidth and thin thickness were simultaneously achieved.

Abstract

The development of broadband and high-efficiency electromagnetic wave absorbing materials in the gigahertz is highly crucial and challenging. Here, typical magnetic-carbon composites were successfully obtained, which involves a controlled reduction process from a semiconductor to magnetic materials under reducing atmosphere. Due to the huge difference in lattice constants, yolk-shell Fe3O4@C and Fe@void@C powders were developed from core-shell a-Fe2O3@PDA precursor. The chemical composition, magnetic property, and morphology of the final magnetic@void@C powders were discussed comprehensively. Related electromagnetic parameters of all samples were tested to analyze the storage and loss ability toward electromagnetic wave energy. Inspiringly, both the Fe3O4@C and Fe@void@C composites exhibited high-performance energy absorption in the microwave band. The minimal reflection loss (RLmin) value of Fe3O4@C is −45.4 dB at the absorber thickness only at 1.5 mm and the efficient absorption (RL ≤−10 dB) frequency up to 5.5 GHz at 2.0 mm thickness. Meanwhile, the RLmin value of Fe@void@C is −66.5 dB at the absorber thickness of only 1.6 mm and show broadband responding arrange, covering almost all the Ku-band. The synthesized magnetic-carbon composites display excellent electromagnetic properties and high-efficient energy conversion behaviors, meeting to the high requirements for modern microwave absorption materials.

Introduction

With the rapid development of the wireless communications industry, the frequency of electromagnetic waves in the GHz ranges for absorbent materials has widely been the concern of people [1], [2], [3], [4], [5], [6], [7]. Presently, broadband and high-efficiency electromagnetic wave absorbing materials are used in the industries, commerce, military and other fields, which have important application value [8], [9], [10], [11]. Recently, many workers pay more attention to the magnetic metals or magnetic metal alloys, which have high magnetic loss capability and magnetocrystalline anisotropy [12], [13], [14], [15], [16]. However, the preparation of electromagnetic wave responding materials matched with strong loss and broadband absorption is very difficult, especially at the thin thickness.

In general, absorbing properties are mainly derived from magnetic loss and dielectric loss [17], [18], [19], [20], [21], [22]. However, the impedance matching of a single dielectric or magnetic loss material is weak. In order to design synthetic high-efficiency absorbing materials, magnetic-dielectric composites are a way to broaden the effective absorption bandwidth and to reduce the density of the final composite. Ji and co-workers synthesized hollow carbon@Fe@Fe3O4 nanospheres as a lightweight microwave absorber [23]. Zhao et al prepared hollow porous Ni@SnO2 hybrids with enhanced electromagnetic absorption properties [24]. Xu et al. fabricated metal organic framework-derived Fe/C nanocubes toward efficient microwave absorption [25]. Kuang et al. reported porous Co/C composites with excellent electromagnetic wave absorption properties [26]. As a typical dielectric loss absorbing material, carbon matrix can prove unique conduction loss and boost polarization loss. The combination of magnetic and carbon materials not only improves the impedance matching of the material but also tunes the microwave absorption performance of composites, including the attenuation intensity and response frequency [27], [28], [29], [30].

Herein, yolk-shell magnetic@viod@C were successfully prepared using original a-Fe2O3@PDA as precursor. Controlling the reduction process, magnetic-dielectric Fe3O4@C and Fe@viod@C composites were obtained after an annealing process. Enhancing the microwave dissipation ability and synergistic effect, Fe@void@C exhibited broadband and high-efficiency absorption behaviors than the Fe3O4@C absorber. The minimal reflection loss value of Fe@void@C is −66.5 dB at the absorber thickness only 1.6 mm. Meanwhile, the efficient absorption frequency covers 5.1 GHz from 12.9 to 18 GHz, which covers almost all the Ku-band. Benefiting from the magnetic loss, dielectric loss and synergistic effect, synthesized magnetic-carbon composites display excellent behaviors toward electromagnetic energy conversion. Regulating electromagnetic parameters and microwave loss capability via controlled reduction can provide new ideas for the preparation of high performance electromagnetic wave absorbing materials.

Section snippets

Materials

All reagents applied in this experiment were analytical grade. Iron(III)chloride hexahydrate (FeCl3·6H2O), Sodium citrate (C6H5Na3O7·2H2O), Sodium acetate (CH3COONa) were obtained from Sinopharm Chemical Reagent Co., Ltd. Tin. Tris-buffer solution (pH = 8.5) and dopamine hydrochloride (C8H12ClNO2) was supplied by Aldrich. Deionized water was gained from a Millipore Mill-Q system.

Synthesis of cube-like Fe2O3 particles

Cube-like Fe2O3 particles were fabricated by a hydrothermal method. Initially, a solution consisting of 0.8 mL NaOH

Results and discussion

The detailed synthesis information of yolk-shell Fe@C composites is depicted in Scheme 1. Firstly, cube-like Fe2O3 particles were gained via a solvothermal reaction. After magnetic stirring in the dopamine hydrochloride Tris-buffer solution at room temperature, polydopamine (PDA) coated on the surface of Fe2O3 particles to fabricated the core–shell Fe2O3@PDA composites, which keep the original cube-like morphology. Secondly, the prepared Fe2O3@PDA composites further annealed in the H2/Ar

Conclusion

In summary, magnetic yolk-shell Fe3O4@C and Fe@void@C composites were successfully obtained via controlled reduction strategy, converting the pure semiconductor Fe2O3@PDA precursor to magnetic-carbon composites. Final magnetic@void@C powders exhibited excellent electromagnetic parameters and enhanced microwave absorption loss ability. Inspiringly, the minimal reflection loss (RLmin) value of yolk-shell Fe3O4@C product up to −45.4 dB at the absorber thickness only 1.5 mm and the EABD frequency

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgment

This work was supported by the National Natural Science Foundation of China (Grant No. 51477002).

References (53)

  • X. Liu et al.

    Facile synthesis of Fe3O4/C composites for broadband microwave absorption properties

    Appl. Surf. Sci.

    (2018)
  • J. Wang et al.

    Heterogeneous interfacial polarization in Fe@ZnO nanocomposites induces high-frequency microwave absorption

    Mater. Lett.

    (2017)
  • Y. Cheng et al.

    Magnetic and electromagnetic properties of Fe3O4/Fe composites prepared by a simple one-step ball-milling

    J. Alloys Compd.

    (2017)
  • Y. Liu et al.

    Enhanced microwave absorption performance of porous and hollow CoNi@C microspheres with controlled component and morphology

    J. Alloys Compd.

    (2019)
  • J. Ma et al.

    A facile fabrication and highly tunable microwave absorption of 3D flower-like Co3O4-rGO hybrid-architectures

    Chem. Eng. J.

    (2018)
  • T. Huang et al.

    Preparation of hierarchically porous carbon/magnetic particle composites with broad microwave absorption bandwidth

    Chem. Eng. J.

    (2019)
  • Y. Zhang et al.

    Hierarchical core-shell Fe3O4@C@MoS2 composites synergistically enhance microwave absorption

    Mater. Lett.

    (2019)
  • X. Wang et al.

    One-pot solvothermal synthesis of Fe/Fe3O4 composites with broadband microwave absorption

    J. Alloys Compd.

    (2019)
  • Y. Zhang et al.

    In situ carbon nanotubes encapsulated metal Nickel as high-performance microwave absorber from Ni–Zn Metal-Organic framework derivative

    J. Alloys Compd.

    (2019)
  • M. Cao et al.

    2D MXenes: electromagnetic property for microwave absorption and electromagnetic interference shielding

    Chem. Eng. J.

    (2019)
  • D. Ding et al.

    Rational design of core-shell Co@C microspheres for high-performance microwave absorption

    Carbon

    (2017)
  • X. Cui et al.

    Stable microwave absorber derived from 1D customized heterogeneous structures of Fe3N@C

    Chem. Eng. J.

    (2020)
  • H. Zhao et al.

    A sustainable route from biomass cotton to construct lightweight and high-performance microwave absorber

    Chem. Eng. J.

    (2018)
  • B. Zhao et al.

    A novel sponge-like 2D Ni/derivative heterostructure to strengthen microwave absorption performance

    Phys. Chem. Chem. Phys.

    (2018)
  • S. Rehman et al.

    Starfish-like C/CoNiO2 heterostructure derived from ZIF-67 with tunable microwave absorption properties

    Chem. Eng. J.

    (2019)
  • H. Lv et al.

    A voltage-boosting strategy enabling a low-frequency, flexible electromagnetic wave absorption device

    Adv. Mater.

    (2018)
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