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Journal of Alloys and Compounds 769 (2018) 961e968
Contents lists available at ScienceDirect
Journal of Alloys and Compounds
journal homepage:
Enhanced electromagnetic wave response of nickel nanoparticles
encapsulated in nanoporous carbon
Bin Quan, Guoyue Xu, Heng Yi, Zhihong Yang**, Junxian Xiang, Yutian Chen, Guangbin Ji*
College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 211100, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 3 July 2018
Received in revised form
3 August 2018
Accepted 7 August 2018
Available online 11 August 2018
Nickel nanoparticles embedded nanoporous carbon (NPC/Ni) was fabricated via thermal treatment of
metal organic framework precursors. Nickel particles were uniformly dispersed in the nanoporous carbon network under certain sintering temperature. Meanwhile, the obtained magnetic metal Ni could
improve the electrical conductivity of carbon due to its graphitization catalysis on amorphous carbon.
The obtained multiple interfaces, porous structures as well as tunable electrical conduction are all
beneficial to the enhanced microwave absorption. The sample prepared at 700 C exhibits nice microwave absorption capacity with the maximum reflection loss (RL) value of 39.4 dB and effective bandwidth of 4.2 GHz. In addition, the prepared sample exhibit huge potential as light absorber. When sample
loading content decreases from 30 wt% to 25 wt%, its maximum RL value reaches 39.4 dB with an
effective bandwidth of 4.2 GHz. This work not only demonstrates that the NPC/Ni composites are
excellent absorbers with wide bandwidth, strong absorption, thin thickness and light weight, but also
initiates a new pathway for artificially designed magnetic metal/dielectrics composites nanostructures
with objective functionalities.
© 2018 Elsevier B.V. All rights reserved.
Ni nanoparticles
Nanoporous carbon
Microwave absorption
1. Introduction
With the growing electromagnetic interference in daily life,
high-efficiency microwave absorbing materials with low thickness,
lightweight, wide absorption frequency and strong absorption capacity are eagerly required [1e3]. Among them, the magnetic/
dielectric composites exhibit huge potential compared to pure
dielectric or magnetic absorbers [4,5]. As we all know, electromagnetic wave absorption
is related to complex permittivity and
permeability Zin ¼ Z0 mr =εr , hence, ideal microwave absorbers
should possess large saturation magnetization/high Curie temperature and moderate permittivity values [6e8]. When the intrinsic
impedance matching is close to the free space impedance, more
microwaves can be introduced into the interior of absorbers [9,10].
Thus the construction of magnetic metal/carbon matrix composites
is to be a reliable option. Of all the magnetic metals, nickel has
attracted broad attention due to its relative high magnetization as
well as tunable size/shape anisotropy [11,12]. However,
* Corresponding author.
** Corresponding author.
E-mail addresses:,
(Z. Yang), (G. Ji).
0925-8388/© 2018 Elsevier B.V. All rights reserved.
conventional fabrication methods are heavily restricted by the extra factors. The solvent reaction is easily affected by solution environment and addition agent [13], and the magnetic metal particles
at the nanoscale tend to reunite into bulk [14]. In consideration of
architectural design, nanoporous structure is favor of the microwave attenuation, however, the traditional template method requires complicated operation procedures [15e17].
In view of the above-mentioned situation, Ni-based CPO-27-M
metal organic framework [18] is used as precursor to construct
the nickel particles embedded nanoporous carbon (NPC/Ni). During
high sintering temperature, Ni nanoparticles are well dispersed
into the nanoporous carbon matrix, and magnetic metal nickel
could also improve the conductivity of carbon by the graphitization
catalysis on amorphous carbon. The sample prepared at 700 C
exhibits excellent performance, whose maximum RL value
is 39.4 dB with an effective bandwidth of 4.2 GHz. When the
sample loading content decreases from 30 wt% to 25 wt%, the
maximum RL value reaches 39.4 dB with an effective bandwidth
of 4.2 GHz, which demonstrates that the prepared sample has huge
potential as light absorbers. This work demonstrates that the NPC/
Ni composites are nice absorbers with wide bandwidth, strong
absorption, thin thickness and light weight. Moreover, it also opens
up a new pathway for artificially designed magnetic metal/
B. Quan et al. / Journal of Alloys and Compounds 769 (2018) 961e968
2. Experiment
2.1. Materials preparation
Synthesis of CPO-27-Ni: 2.9 g 2, 5-dihydroxyterephthalic acid
was dissolved in 50 mL of THF to obtain solution A. Then 7.4 g
Ni(CH3COOH)2$4H2O was added in 50 mL distilled water to form
solution B. The obtained mixed solution (solution A þ solution B)
was heated at 100 C for 72 h. Yellow powder can be obtained after
filtration with water as well as subsequent drying at vacuum oven.
Synthesis of NPC/Ni composites: The as-prepared CPO-27-Ni
composites were calcinated at 700, 800, 900 C for at N2 atmosphere with the heating rate of 3 C min 1, and the obtained nickel
particles embedded nanoporous carbon (NPC/Ni) was denoted as
S700, S800 and S900, respectively.
2.2. Measurement
The as-obtained samples were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission
electron microscopy (TEM), Raman spectroscopy, BET and so on.
Electromagnetic parameters were detected using Agilent PNA
N5244A vector network analyze. The mixture was previously synthesized by homogeneously mixing wax and samples, then compacted them into toroidal-shaped samples (Fin: 3.04 mm, Fout: 7).
3. Results and discussion
Sample S700, S800 and S900 were obtained by calcining the
same precursor CPO-27-Ni at various temperatures (700, 800,
900 C). As can be seen from Fig. 1, three samples basically maintain
the identical diffraction peak of Ni [19], which demonstrates that
the crystal structures of as-obtained NPC/Ni composites largely
remain the same when prepared at different temperatures. In
addition, carbon peak could not been found in the XRD patterns,
which is derived from its amorphous feature. In addition, the stability of sample was also tested. As seen in Fig. S2, the XRD pattern
of S700 exposed in heating oven at 50 C for one week (S700-One
week) exhibits similar crystal structure as that of S700, indicating
the relative stability of NPC/Ni composites.
The existence of carbon matrix and the effect of preparation
condition on carbon graphitization degree were further
Fig. 1. XRD patterns of sample S700, S800 and S900.
Fig. 2. Raman spectra of sample S700, S800 and S900.
characterized by Raman spectra (Fig. 2). The samples treated at
various temperatures display different graphitization characteristics, as revealed by the typical carbon features of D band
(1356 cm1) and G band (1554 cm1). G band, first-order scattering
of E2g phonons by sp2 carbon atoms, is on behalf of graphite; and D
band, breathing mode of k-point photons of A1g symmetry, signifies
the amorphous forms [20]. As can be seen from the calculation
results, the intensity ratio of D band to G band is 1.33, 1.26 and 1.18
for S700, S800 and S900, respectively, which is cause by the
increasing defect as rising temperature.
SEM images of the precursor CPO-27-Ni and S700, S800 as well
as S900 were provided in Fig. 3. Laminated NPC/Ni composites
(Fig. 3d, e, g, h, j, k) were obtained after the heat treatment of bulk
CPO-27-Ni composites (Fig. 3aec) at different calcinations temperature. Obvious nanoparticles embedded in the carbon matrix
can be observed in Fig. 3f, i, l, which may be derived from the nickel
nanoparticles as demonstrated in the XRD patterns. More clear
porous structures of Ni particles dispersed carbon texture can be
seen in Fig. 4aed. Clear interfaces between carbon matrix and Ni
particles can be seen from Fig. S3, which is beneficial to the generation of interfacial polarization and enhanced microwave absorption. In addition, the EDS elemental mapping of C, N, Ni for the
selected image (Fig. 4e) are exhibited in Fig. 4feh to demonstrate
the distribution of each element in prepared sample. Obviously,
Nickel particles are homogeneously distributed in the carbon
sheets with N element doping, revealed by the uniform distribution
of C, N, Ni.
Nitrogen adsorption-desorption measurements were conducted
to evaluate the variation of specific surface as well as porosity
features of three NPC/Ni composites. Typical IUPAC type IV pattern
with sharp upturn in high-relative-pressure region [21] can be
found in all the samples, as shown in Fig. 5aec. The BET surface
areas of NPC/Ni composites are 112.9311 m2/g, 149.0714 m2/g,
136.3568 m2/g, respectively (Fig. 5def). Moreover, the pore size
distribution based on BJH method exhibits the average pore size is
in mesoporous range (23.07314 nm, 19.39422 nm, 20.26114 nm). All
the above-mentioned information indicates the nanoporous characteristics of NPC/Ni composites, which makes for the dissipation of
incident microwave [22].
Electromagnetic wave absorbing capacity is closely related to
the electromagnetic parameters [23,24]. Fig. 6a and b exhibit the
histograms of ε0 values and ε00 values for three samples at S, C, X,
B. Quan et al. / Journal of Alloys and Compounds 769 (2018) 961e968
Fig. 3. SEM images of precursors (aec), S700 (def), S800 (gei) and S900 (jel) at different magnification.
Fig. 4. TEM images of S700 at the magnification of 1.0 mm (a), 0.5 mm (b), 0.2 mm (c) and 100 nm (d). Corresponding elemental mapping of elements C (f), N (g), Mg (h) for the
selected image (e).
and Ku bands. Gradually increasing complex permittivity values at
all measured bands can be observed from S700, S800 to S900,
which demonstrates the improving storage capacity of electrical
energy and dielectric loss ability. Accordingly, electrical conductivity of three samples are also obtained based on the conductivity
equation: s ¼ εo ε00 w ¼ 2εo ε00 pf , which exhibits the same trend as
that of complex permittivity, as can be seen from Fig. S1. Complex
permeability values are also presented in Fig. 6c and d. The roughly
same m0 values m00 values demonstrate that nanoscale nickel particles embedded in carbon matrix do not possess big differences in
magnetic energy storage as well as magnetic loss ability.
The microwave reflection maps of NPC/Ni composites, as shown
in Fig. 7aec, exhibit that the samples have huge dependence on
matching thickness and frequency. As the matching thickness and
B. Quan et al. / Journal of Alloys and Compounds 769 (2018) 961e968
Fig. 5. N2 adsorption-desorption isotherms and corresponding BJH pore-size distribution of S700 (a, d); S800 (b, e) and S900 (c, f).
frequency changing, the related microwave absorption capacities
vary a lot. Moreover, the microwave absorbing activity decreases
from S700 to S900, and sample S700 shows the optimal performance with maximum absorption value of 20.65 dB at 1.4 mm
and effective absorption bandwidth of 3.28 GHz.
Magnetic dissipation mechanisms were detected by the
of 10 kOe < H < 10 kOe for the three samples. As shown in Fig. 8,
the saturation magnetization (Ms) values of S700, S800 and S900
(36.8, 35.1, and 32.3, respectively) are lower than some reported
saturation magnetization values of Ni nanoparticles due to the
smaller size of nickel particles and massive carbon matrix in the
composites. Furthermore, the coercivity (Hc) values are 224.1, 93.1,
and 136.3 Oe, respectively, which is due to the crystalline anisotropy and shape anisotropy. Due to the relatively weak loss ability
compared to that of permittivity loss, the magnetic parameters
could not exhibit big influence on magnetic dissipation activity.
In order to explore the intrinsic attenuation mechanisms, the
frequency dependence of dielectric/magnetic tangent (tandε, a/
tandm, b), attenuation constant (c) and impedance matching ratio
(d) were gained by the following equations [9,25,26]:
tan dε ¼ ε
tan dm ¼ m
00 00
00 00
ðm ε m0 ε0 Þ þ ðm ε m0 ε0 Þ2 þ ðm0 ε þ m ε0 Þ2
Z ¼ Z0
mr =εr
B. Quan et al. / Journal of Alloys and Compounds 769 (2018) 961e968
Fig. 6. Histograms of real permittivity (a) and imaginary permittivity (b) values at various microwave bands for three NPC/Ni composites. Real (c) and imaginary (d) permeability
curves for NPC/Ni composites at 2e18 GHz.
Fig. 7. Microwave reflection maps of S700 (a), S800 (b) and S900 (c).
As can be seen from Fig. 9a and b, the dielectric dissipation capacity varies a lot and can be ranked as S900 > S800 > S700, while
the magnetic loss ability has little difference [27]. Likewise, the
comprehensive dissipation capacity, expressed by attenuation
constant, is also ranked as that of dielectric loss ability (Fig. 9c).
Impedance matching is also explored as shown in Fig. 9d. It can be
found that the three samples exhibit opposite trend compared to
dissipation ability, and can be ranked as S700 > S800 > S900.
Therefore, it can be concluded that one-sided pursuit of strong loss
ability is not rational behaviors. An excellent absorber needs both
impedance matching and dissipation capacity at the same time.
Relatively low ε0 value can result in nice impedance matching;
however, it could not provide enough loss ability to dissipate the
incident microwave, finally making little contribution to effective
microwave absorption [10].
In order to further explore the potential application in light
absorbing materials, the electromagnetic behaviors for sample
S700 with 30 wt%/20 wt% of paraffin loading were compared. As
shown in Fig. 10a and b, both of the complex permittivity and
Fig. 8. MH loops measure of three samples measured at room temperature.
B. Quan et al. / Journal of Alloys and Compounds 769 (2018) 961e968
Fig. 9. Dielectric (a) and magnetic (b) loss factor, attenuation constant (c) and impedance matching ratio (d) of NPC/Ni composites.
Fig. 10. Electromagnetic parameters (ε0 , ε0 0 , m0 , m00 ) of S700/70 wt% (a) and S700/75 wt% paraffin composites; attenuation constant (c) and dielectric loss factor (d) of S700 with
different paraffin loading.
permeability decrease when the paraffin loading content increases
from 70 wt% to 75 wt%, which is derived from the microwave
penetrating effect of wax [28]. In view of that dielectric constant act
as a dominant role in microwave dissipation, the integral loss
ability of S700/70 wt% composites should be higher than that of
S700/75 wt% composites, which can be confirmed by the
B. Quan et al. / Journal of Alloys and Compounds 769 (2018) 961e968
Fig. 11. 3D reflection loss curves of S700/70 wt% (a) and S700/75 wt% paraffin composites.
attenuation constant, and dielectric loss factor as shown in Fig. 9c
and d.
3D reflection loss curves of S700/70 wt% and S700/75 wt%
paraffin composites are plotted. As can be seen from Fig. 11, the
sample S700/75 wt% paraffin composites exhibit much enhanced
microwave absorption performance compared to that of S700/
70 wt%
reaches 39.4 dB with an effective bandwidth of 4.2 GHz, which
demonstrate that the prepared sample has huge potential as light
4. Conclusion
Thermal treatment of metal organic framework was performed
to prepare Ni nanoparticles embedded nanoporous carbon (NPC/
Ni). Uniformly dispersed nickel particles in nanoporous carbon can
be obtained during certain pyrolysis temperature. The introduction
of metal nickel can effectively regulate the electrical conductivity.
With multiple interfaces, tunable conduction and porous structures, excellent microwave absorption performance can be gained.
The maximum RL value of 39.4 dB and effective bandwidth of
4.2 GHz could be obtained when calcining at 700 C. When paraffin
loading content increases from 70 wt% to 75 wt%, the maximum RL
value reaches 39.4 dB with an effective bandwidth of 4.2 GHz,
which demonstrates that the prepared sample has huge potential
as light absorbers. This work demonstrates that the NPC/Ni composites are nice absorbers with wide bandwidth, strong absorption,
thin thickness and light weight. Moreover, it also opens up a new
pathway for artificially designed magnetic metal/dielectrics composites nanostructures with objective functionalities.
Financial supports from the National Nature Science Foundation
of China (No.:11575085, 51602154), the Aeronautics Science Foundation of China (2017ZF52066), the Qing Lan Project, Six Talent
Peaks Project in Jiangsu Province (No.: XCL-035), Funding for
Outstanding Doctoral Dissertation in NUAA (BCXJ 18-07), and the
Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) are gratefully acknowledged.
Appendix A. Supplementary data
Supplementary data related to this article can be found at
[1] X.G. Liu, C.Y. Cui, J.Y. Yu, Y.P. Sun, A.L. Xia, Ag3PO4 sub-microcubic/SrFe12O19
hexagon nanoflake heterostructure for broadband electromagnetic absorber
at GHz frequency, Mater. Lett. 225 (2018) 1e4.
[2] Z.Y. Huang, H.H. Chen, Y. Huang, Z. Ge, Y. Zhou, Y. Yang, P.S. Xiao, J.J. Liang,
T.F. Zhang, Q. Shi, G.H. Li, Y.S. Cheng, Ultra-broadband wide-angle terahertz
absorption properties of 3D graphene foam, Adv. Funct. Mater. 28 (2018)
[3] P.Y. Liu, L.C. Li, L.M. Wang, T. Huang, Q.L. Zhao, K.L. Zhang, X.M. Bian, Z.L. Hou,
Broadening electromagnetic absorption bandwidth: design from microscopic
dielectric-magnetic coupled absorbers to macroscopic patterns, Phys. Status
Solidi A 214 (2017) 1700589e1700598.
[4] X.G. Liu, J.Y. Yu, C.Y. Cui, Y.P. Sun, X.L. Li, Z.X. Li, Flower-like BiOI microsphere/
Ni@C nanocapsule hybrid composites and their efficient microwave absorbing
activity, J. Phys. D Appl. Phys. 51 (2018), 265002.
[5] B. Quan, X.H. Liang, H. Yi, H. Gong, G.B. Ji, J.B. Chen, G.Y. Xu, Y.W. Du, Constructing hierarchical porous nanospheres for versatile microwave response
approaches: the effect of architectural design, Dalton Trans. 46 (2017)
[6] T. Liu, Y. Pang, M. Zhu, S. Kobayashi, Microporous Co@CoO nanoparticles with
superior microwave absorption properties, Nanoscale 6 (2014) 2447e2454.
[7] S. Xie, X.N. Guo, G.Q. Jin, X.J. Guo, Carbon coated CoeSiC nanocomposite with
high-performance microwave absorption, Phys. Chem. Chem. Phys. 15 (2013)
[8] Y.B. Zhang, P. Wang, Y. Wang, L. Qiao, T. Wang, F.S. Li, Synthesis and excellent
electromagnetic wave absorption properties of parallel aligned FeCo@C
coreeshell nanoflake composites, J. Mater. Chem. C 3 (2015) 10813e10818.
[9] B. Quan, G.Y. Xu, D.R. Li, W. Liu, G.B. Ji, Y.W. Du, Incorporation of dielectric
constituents to construct ternary heterojunction structures for high-efficiency
electromagnetic response, J. Colloid Interface Sci. 498 (2017) 161e169.
[10] B. Quan, X.H. Laing, G.Y. Xu, Y. Cheng, Y.N. Zhang, W. Liu, G.B. Ji, Y.W. Du,
A permittivity regulating strategy to achieve high-performance electromagnetic wave absorbers with compatibility of impedance matching and energy
conservation, New J. Chem. 41 (2017) 1259e1266.
[11] S. Qiu, H.L. Lyu, J.R. Liu, Y.Z. Liu, N.N. Wu, W. Liu, Facile synthesis of porous
nickel/carbon composite microspheres with enhanced electromagnetic wave
absorption by magnetic and dielectric losses, ACS Appl. Mater. Interfaces 8
(2016) 20258e20266.
[12] H.B. Zhao, Z.B. Fu, H.B. Chen, M.L. Zhong, C.Y. Wang, Excellent electromagnetic
absorption capability of Ni/carbon based conductive and magnetic foams
synthesized via a green one pot route, ACS Appl. Mater. Interfaces 8 (2016)
[13] J.A. Zhang, Y. Song, M. Kopec, J. Lee, Z.Y. Wang, S.Y. Liu, J.J. Yan, R. Yuan,
T. Kowalewski, M.R. Bockstaller, K. Matyjaszewski, J. Am. Chem. Soc. 139
(2017) 12931e12934.
[14] X.G. Liu, S.L. Ran, J.Y. Yu, Y.P. Sun, Multiscale assembly of Fe2B porous microspheres for large magnetic losses in the gigahertz range, J. Alloys Compd.
765 (2018) 943e950.
[15] X.G. Liu, X.L. Li, J.Y. Yu, Y.P. Sun, Ultrasmall Sn nanoparticles embedded in Ndoped carbon nanospheres as long cycle life anode for lithium ion batteries,
Mater. Lett. 223 (2018) 203e206.
[16] B. Quan, X.H. Liang, G.B. Ji, Y.N. Zhang, G.Y. Xu, Y.W. Du, Cross-linking-derived
synthesis of porous CoxNiy/C nanocomposites for excellent electromagnetic
behaviors, ACS Appl. Mater. Interfaces 9 (2017) 38814e38823.
[17] J.Y. Yu, X.L. Li, Y.P. Sun, X.G. Liu, CoS@sulfur doped onion-like carbon nanocapsules with excellent cycling stability and rate capability for sodium-ion
batteries, Ceram. Int. 2018.06.163.
[18] P.D.C. Dietzel, V. Besikiotis, R. Blom, Application of metaleorganic frameworks
with coordinatively unsaturated metal sites in storage and separation of
methane and carbon dioxide, J. Mater. Chem. 19 (2009) 7362e7370.
B. Quan et al. / Journal of Alloys and Compounds 769 (2018) 961e968
[19] R. Das, P. Pachfule, R. Banerjee, P. Poddar, Metal and metal oxide nanoparticle
synthesis from metal organic frameworks (MOFs): finding the border of metal
and metal oxides, Nanoscale 4 (2012) 591e599.
[20] B. Quan, W. Liu, Y.S. Liu, Y. Zheng, G.C. Yang, G.B. Ji, Quasi-noble-metal graphene quantum dots deposited stannic oxide with oxygen vacancies: synthesis and enhanced photocatalytic properties, J. Colloid Interface Sci. 481
(2016) 13e19.
[21] B. Quan, X.H. Liang, J. Lv, S.S. Dai, G.Y. Xu, Y.W. Du, Laminated graphene oxidesupported high-efficiency microwave absorber fabricated by an in situ growth
approach, Carbon 129 (2018) 310e320.
[22] B. Zhao, B.B. Fan, Y.W. Xu, G. Shao, X.D. Wang, W.Y. Zhao, R. Zhang, Preparation of honeycomb SnO2 foams and configuration-dependent microwave
absorption features, ACS Appl. Mater. Interfaces 7 (2015) 26217e26225.
[23] R.B. Wu, Z.H. Yang, M.S. Fu, K. Zhou, In-situ growth of SiC nanowire arrays on
carbon fibers and their microwave absorption properties, J. Alloys Compd. 687
(2016) 833e838.
[24] M.A. Kashi, M.H. Mokarian, S.A. Arani, Improvement of the microwave absorption properties in FeNi/PANI nanocomposites fabricated with different
structures, J. Alloys Compd. 742 (2018) 413e420.
[25] B. Quan, X.H. Liang, G.B. Ji, J.N. Ma, P.Y. Ouyang, H. Gong, G.Y. Xu, Y.W. Du,
Strong electromagnetic wave response derived from the construction of
dielectric/magnetic media heterostructure and multiple interfaces, ACS Appl.
Mater. Interfaces 9 (2017) 9964e9974.
[26] J.T. Feng, Y.H. Hou, T.C. Wang, L.C. Li, Synthesis of hierarchical ZnFe2O4@SiO2
@RGO coreshell microspheres for enhanced electromagnetic wave absorption, ACS Appl. Mater. Interfaces 9 (2017) 14103e14111.
[27] B. Quan, X.H. Liang, G.B. Ji, Y. Cheng, W. Liu, J.N. Ma, Y.N. Zhang, D.R. Li, G.Y. Xu,
Dielectric polarization in electromagnetic wave absorption: review and
perspective, J. Alloys Compd. 728 (2017) 1065e1075.
[28] W.L. Song, L.Z. Fan, M.S. Cao, M.M. Lu, C.Y. Wang, J. Wang, T.T. Chen, Y. Li,
Z.L. Hou, J. Liu, Y.P. Sun, Facile fabrication of ultrathin graphene papers for
effective electromagnetic shielding, J. Mater. Chem. C 2 (2014) 5057e5064.
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