Synthesis of Hierarchical ZnFe2O4@SiO2@RGO Core–Shell Microspheres for Enhanced Electromagnetic Wave Absorption

Feng, Jie; Hou, Yanhui; Wang, Yechen; Li, Liangchao

doi:10.1021/acsami.7b03330

Cited by 175 publications

(55 citation statements)

References 44 publications

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“…Zhang et al [ 23 ] designed the RGO/MnFe 2 O 4 composite with an EAB of 4.88 GHz and a minimum reflection loss (RL) of −30 dB. Feng et al [ 24 ] coated ZnFe 2 O 4 with SiO 2 and RGO, which exhibited an EAB of 6 GHz and a minimum RL of -43.9 dB. However, no attention has been paid to the microstructure design of individual graphene, which might have a great impact upon the MA performance.…”

Section: Introductionmentioning

confidence: 99%

Porous Graphene Microflowers for High-Performance Microwave Absorption

et al. 2017

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Graphene has shown great potential in microwave absorption (MA) owing to its high surface area, low density, tunable electrical conductivity and good chemical stability. To fully realize grapheneʼs MA ability, the microstructure of graphene should be carefully addressed. Here we prepared graphene microflowers (Gmfs) with highly porous structure for high-performance MA filler material. The efficient absorption bandwidth (reflection loss ≤ −10 dB) reaches 5.59 GHz and the minimum reflection loss is up to −42.9 dB, showing significant increment compared with stacked graphene. Such performance is higher than most graphene-based materials in the literature. Besides, the low filling content (10 wt%) and low density (40–50 mg cm−3) are beneficial for the practical applications. Without compounding with magnetic materials or conductive polymers, Gmfs show outstanding MA performance with the aid of rational microstructure design. Furthermore, Gmfs exhibit advantages in facile processibility and large-scale production compared with other porous graphene materials including aerogels and foams. Electronic supplementary materialThe online version of this article (10.1007/s40820-017-0179-8) contains supplementary material, which is available to authorized users.

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Section: Introductionmentioning

confidence: 99%

Porous Graphene Microflowers for High-Performance Microwave Absorption

et al. 2017

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“…[40] Moreover, the intensity ratio for Co@NC@RGO composite (I D / 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 I G = 0.94) is higher than that of pure GO (I D /I G = 0.63), suggesting the successful transformation of GO to RGO through pyrolysis. [41] The morphology and structure of the Co@NC@RGO composites were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Co@NC spheres were well distributed onside the graphene sheets and the aggregation extents of the Co@NC nanospheres declined gradually with the RGO amount increasing (Figure 3a wrapped by the N-doped graphitized carbon to form core-shell Co@NC nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

High‐Performance Microwave Absorption of MOF‐Derived Core‐Shell Co@N‐doped Carbon Anchored on Reduced Graphene Oxide

Liu

Wang

et al. 2019

ChemNanoMat

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Nanocomposites of MOF-derived N-doped-carbonwrapped cobalt anchored on reduced graphene oxide (Co@NC@RGO) have been successfully fabricated for use as microwave absorption materials. A unique core-shell nanostructure with cobalt nanoparticles as core and N-doped graphitized carbon as shell was grown on the surface of laminated reduced graphene oxide (RGO). An enhanced synergistic effect between magnetic and dielectric components can be readily achieved by changing the dispersion of Co@NC nanoparticles on RGO. The as-synthesized microspheres are composed of numerous nanoscale core-shell Co@NC units, which combined magnetic Co cores with intrinsically contributing magnetic loss and N-doped graphitized carbon providing a pathway for electron transfer as well as transition between magnetic Co cores and high electrical conductivity of RGO. The resulting Co@NC@RGO composites exhibit excellent reflection loss (RL) values and effective absorption bandwidths. The optimized Co@NC@RGO-3 minimum RL (RLmin) value could reach À 46.5 dB at 9.4 GHz with a thickness of 3.5 mm. Tuning the thickness from 1.5-5 mm, the effectivity absorption frequency range could achieve up to 14.3 GHz (from 3.7 to 18 GHz). The excellent microwave absorption performance may be attributed to the magnetic loss, dielectric loss and interfacial polarization.[a] L.

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“…The improved conductivity is helpful to enhance dielectric relaxation and dipole polarization, leading to the evidently increased permittivity of annealed samples. The enhanced permittivity is believed to be beneficial for the improvement of the dielectric loss and electromagnetic absorption performance 27 , 50 . Furthermore, the enhanced conductivity could cause conductive loss 51 , which is also beneficial to improve the electromagnetic wave absorption performance of CoNi@TiO 2 microspheres.…”

Section: Resultsmentioning

confidence: 99%

Rational Construction of Uniform CoNi-Based Core-Shell Microspheres with Tunable Electromagnetic Wave Absorption Properties

Chen

Jiang

et al. 2018

Sci Rep

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Core-shell particles with integration of ferromagnetic core and dielectric shell are attracting extensive attention for promising microwave absorption applications. In this work, CoNi microspheres with conical bulges were synthesized by a simple and scalable liquid-phase reduction method. Subsequent coating of dielectric materials was conducted to acquire core-shell structured CoNi@TiO2 composite particles, in which the thickness of TiO2 is about 40 nm. The coating of TiO2 enables the absorption band of CoNi to effectively shift from Ku to S band, and endows CoNi@TiO2 microspheres with outstanding electromagnetic wave absorption performance along with a maximum reflection loss of 76.6 dB at 3.3 GHz, much better than that of bare CoNi microspheres (54.4 dB at 17.8 GHz). The enhanced EMA performance is attributed to the unique core-shell structures, which can induce dipole polarization and interfacial polarization, and tune the dielectric properties to achieve good impedance matching. Impressively, TiO2 coating endows the composites with better microwave absorption capability than CoNi@SiO2 microspheres. Compared with SiO2, TiO2 dielectric shells could protect CoNi microspheres from merger and agglomeration during annealed. These results indicate that CoNi@TiO2 core-shell microspheres can serve as high-performance absorbers for electromagnetic wave absorbing application.

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Synthesis of Hierarchical ZnFe₂O₄@SiO₂@RGO Core–Shell Microspheres for Enhanced Electromagnetic Wave Absorption

Cited by 175 publications

References 44 publications

Porous Graphene Microflowers for High-Performance Microwave Absorption

Porous Graphene Microflowers for High-Performance Microwave Absorption

High‐Performance Microwave Absorption of MOF‐Derived Core‐Shell Co@N‐doped Carbon Anchored on Reduced Graphene Oxide

Rational Construction of Uniform CoNi-Based Core-Shell Microspheres with Tunable Electromagnetic Wave Absorption Properties

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