Physicochemical properties and microwave absorption performance of Co3O4 and banana peel-derived porous activated carbon composite at X-band frequency

Yusuf, Jemilat Yetunde; Soleimani, Hassan; Chuan, Lee Kean; Sanusi, Yekinni Kolawole; Adebayo, Lawal Lanre

doi:10.1016/j.jallcom.2021.161474

Cited by 44 publications

(15 citation statements)

References 61 publications

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“…46 Furthermore, several obvious relaxation peaks appear in the ε″ curve, indicating the existence of various polarization processes inside the materials. 47 Similarly, the complex permittivity of HCF@NC/Co-700 with different filler loading also presents the same frequency-dependent behavior (Figure S9a,b). Furthermore, it should be noted that both ε′ and ε″ are significantly enhanced with increasing the calcination temperature or filler loading, indicating that a high carbonization temperature or high filler loading can effectively improve the electric storage and dissipation capacity.…”

Section: Resultsmentioning

confidence: 52%

“…Here, interfacial polarization loss originates from the accumulation of electrons at the HCF-NC/Co, air−carbon, nitrogen−carbon, and Co−carbon interfaces under the applied electric field, and the dipole polarization loss stems from the rearrangement of the electric dipole moment due to the existence of doped N, Co particle, and crystalline defects in graphitic carbon. 47 Based on the Debye theory, ε′−ε″ curves (Cole−Cole plots) of different HCF@NC/Co were drawn using the following equation to further investigate their dielectric loss behavior 16,40…”

Section: Resultsmentioning

confidence: 99%

“…To sum up, a good balance between the impedance matching and attenuation constant is the key factor that enables as much as EMW to enter into the material to be attenuated effectively, giving a reasonable explanation about why HCF@NC/Co-800 at 10% loading and HCF@NC/Co-700 at 14% loading possess the optimum EMW absorption capacity. Furthermore, the EMW absorption mechanism of HCF@ NC/Co-800 was further analyzed using the quarter-wavelength cancellation model, of which the matching thickness (t m ) and the frequency corresponding to RL min (f m ) can meet eq 6, 47,56 and the incident and reflected electromagnetic wave at the air− absorber interface are out of phase by 180°, achieving the total offset of reflected EMW and excellent absorption capacity.…”

Section: Resultsmentioning

confidence: 99%

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Hierarchical HCF@NC/Co Derived from Hollow Loofah Fiber Anchored with Metal–Organic Frameworks for Highly Efficient Microwave Absorption

Guo

Wang

et al. 2021

ACS Appl. Mater. Interfaces

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Hierarchical electromagnetic wave (EMW) absorption materials with a dielectric−magnetic dual-loss mechanism are promising candidates for highly efficient EMW attenuation. Herein, hierarchical dielectric−magnetic composite hollow carbon fiber@nitrogen-doped carbon/Co (HCF@NC/Co) was successfully synthesized via in situ growth of two-dimensional (2D) Co metal−organic framework (MOF) (ZIF-67) nanosheets on the surface of hollow loofah fiber (HLF), followed by a calcination process, where the aggregation of carbonized MOFs was effectively avoided to construct a homogeneous hierarchical onedimensional structure. Based on the advantages of the carbon/Co dielectric−magnetic dual-loss mechanism that results in good impedance matching and multiple polarization loss arising from the extensive heterointerfaces (e.g., HCF-NC/Co, air−carbon, nitrogen−carbon, and Co−carbon interfaces), dipole active sites (e.g., doped N, Co particle, and crystalline defects in graphitic carbon), and hierarchical porous structures, optimal EMW absorption performance of HCF@NC/Co is achieved through regulating the calcination temperature and filler content, where the HCF@NC/Co calcinated at 700 °C exhibits a minimum reflection loss (RL min ) value of −50.14 dB with only 14% filler loading and 2.25 mm thickness, and the maximum effective absorption bandwidth (EAB max ) also reaches 7.36 GHz. Meanwhile, adjustable EAB can also be achieved by optimizing the sample thickness, making it applicable in a wider frequency region. It is expected that our prepared HCF@NC/Co might shed light on designing lightweight and highly efficient EMW MOF-derived EMW absorbing materials.

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Section: Resultsmentioning

confidence: 52%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Hierarchical HCF@NC/Co Derived from Hollow Loofah Fiber Anchored with Metal–Organic Frameworks for Highly Efficient Microwave Absorption

Guo

Wang

et al. 2021

ACS Appl. Mater. Interfaces

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“…[ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ] It is widely acknowledged that the requirements for excellent EM wave absorbers are well‐matched impedance and strong attenuation capacity. [ 11 , 12 , 13 , 14 , 15 ] For the former, when EM wave travels from air media to absorbers’ surface, impedance match means that the impedance of absorbing materials should close to the impedance of air. As known, air media shows no EM wave attenuation ability.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Loss Mechanism in Electromagnetic Wave Absorbing Materials

2022

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Electromagnetic (EM) wave absorbing materials play an increasingly important role in modern society for their multi-functional in military stealth and incoming 5G smart era. Dielectric loss EM wave absorbers and underlying loss mechanism investigation are of great significance to unveil EM wave attenuation behaviors of materials and guide novel dielectric loss materials design. However, current researches focus more on materials synthesis rather than in-depth mechanism study. Herein, comprehensive views toward dielectric loss mechanisms including interfacial polarization, dipolar polarization, conductive loss, and defect-induced polarization are provided. Particularly, some misunderstandings and ambiguous concepts for each mechanism are highlighted. Besides, in-depth dielectric loss study and novel dielectric loss mechanisms are emphasized. Moreover, new dielectric loss mechanism regulation strategies instead of regular components compositing are summarized to provide inspiring thoughts toward simple and effective EM wave attenuation behavior modulation.

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“…It is well known that excellent EMW absorption performance can be achieved when the matching frequency ( f m ) and matching thickness ( t m ) of the RL curve peak meet the following quarter-wavelength cancelation formula: 51 where t m represents the matching thickness, f m refers to the matching frequency, c indicates the speed of light in the free space, and λ is the wavelength of the microwave. Fig.…”

Section: Resultsmentioning

confidence: 99%

Facile preparation of a cellulose derived carbon/BN composite aerogel for superior electromagnetic wave absorption

et al. 2022

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Physicochemical properties and microwave absorption performance of Co3O4 and banana peel-derived porous activated carbon composite at X-band frequency

Cited by 44 publications

References 61 publications

Hierarchical HCF@NC/Co Derived from Hollow Loofah Fiber Anchored with Metal–Organic Frameworks for Highly Efficient Microwave Absorption

Hierarchical HCF@NC/Co Derived from Hollow Loofah Fiber Anchored with Metal–Organic Frameworks for Highly Efficient Microwave Absorption

Dielectric Loss Mechanism in Electromagnetic Wave Absorbing Materials

Facile preparation of a cellulose derived carbon/BN composite aerogel for superior electromagnetic wave absorption

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