Nanomaterials
·
2020
·Vol. 10
·期 1
·166
·
IF 4.324
Hui Liu,Guangzhen Cui,Ling Li,Zhi Zhang,Xuliang Lv,Xinxin Wang
Cobalt sulfide composites have exhibited great potential in terms of microwave absorption, owing to their low price, relatively high capacitance, and excellent electrocatalytic activity. Thus, a novel core-shell like structure comprising cobalt sulfide@polypyrrole (CoS@PPy) composite was synthesized by a facile solvothermal synthesis method and in situ polymerization. When coated by the heterostructure polypyrrole aerogel, CoS@PPy composite exhibited excellent microwave absorption properties with an optimal reflection loss (RL) of −41.8 dB at 6.96 GHz. Furthermore, the absorption bandwidth (RL< −10 dB) of 5.4 GHz could be reached at a coating thickness of 2.05 mm, probably attributing to the synergistic effect of good impedance matching, interfacial polarization, dipole polarization, and conductivity loss. Moreover, this work proposed a loss mechanism mode which probably occurred in the CoS@PPy composites. It was demonstrated that the CoS@PPy composite is a promising material in the field of electromagnetic wave absorption.Keywords:microwave absorption;CoS;PPy;core-shell structure
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2021
·
IF 8.067
Fan Wang,Weihua Gu,Jiabin Chen,Qianqian Huang,Mingyang Han,Gehuan Wang,Guangbin Ji
Perovskite LaCoO 3 is of great potential in electromagnetic wave absorption considering its outstanding dielectric loss as well as the existing magnetic response with the magnetic doping. However, the dissipation mechanism of the magnetic doping on the microwave absorption is lack of sufficient investigated. In this paper, LaCo 1- x Fe x O 3 ( x =0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, LCFOs) perovskites with different Fe doping amounts were prepared successfully by the sol-gel method and subsequent heat treatment in the air atmosphere. The structure characterization carried out by the first-principles calculations shows the effect of Fe doping on the dielectric and magnetic properties of LCFOs and the strong hybridization of Co/Fe-3d with O-2p in the LCFOs system was successfully demonstrated. Particularly, when x =0.1 and the thickness is only 1.95 mm, the LaCo 0.9 Fe 0.1 O 3 exhibits the best microwave absorption performance with the minimum reflection loss (RL) value of about -41 dB. The typical samples achieve a broad effective absorption bandwidth (EAB) of 5.16 GHz (7.92-13.08 GHz), which covers the total X band (8-12 GHz). Considering that, the especial Fe doping perovskite is promising to be a candidate as efficient microwave absorbers.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2024
·
IF 4.2
Yang Guo,Rui Zhou
Corrosion-resistant ferromagnetic absorbers (FMAs) with self-healing properties are crucial for enhancing their durability under harsh conditions. Herein, we fabricated lychee-like FeSiAl (FSA)@C@SiO 2 @1H-Benzotriazol (BTA) coupled with multiple heterogeneous interfaces by coating FSA with a C@SiO 2 @BTA layer using sol-gel, thermal reduction, and molecular encapsulation techniques. The FSA@C@SiO 2 @BTA showed superior microwave absorption (MA) performance than FSA, with a widest absorption bandwidth of 10.44 GHz at 1.98 mm and a maximum reflection loss of −57.81 dB at 2.98 mm. The enhanced MA performance was due to the better impedance matching and the synergistic effects of interfacial and dipole polarization induced by the C@SiO 2 @BTA layer. Moreover, the FSA@C@SiO 2 @BTA exhibited a remarkable corrosion resistance, with a corrosion rate of 3.28 × 10 −10 m/s, which was two orders of magnitude lower than that of FSA, and a corrosion protection efficiency of 99.0 %. The epoxy resin coating containing FSA@C@SiO 2 @BTA also demonstrated a self-healing ability within 5 min after being damaged mechanically. This study presents a novel model that integrates MA, corrosion resistance, and self-healing, heralding new avenues for developing corrosion-resistant FMAs in marine applications.
研究领域:
材料科学
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腐蚀与防护
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 19
·4633
·
IF 4.2
Yan-Fang Li,Li-Fang Wang,Shu-Juan Gao,Tan-Lai Yu,Qi-Feng Li,Jun-Wei Wang
A Co-doped porous carbon was successfully fabricated by a facile carbonizing procedure using coal hydrogasification semi-coke (SC) as the carbon and cobalt nitrate as the magnetic precursors, respectively. The mass ratio of the precursors was changed to regulate the microwave absorption (MA) capabilities. The favorable MA capabilities are a result of a synergistic interaction be-tween the dielectric loss from the carbon framework, the magnetic loss from nano-sized Co particles, and multiple scattering from the residual pores. At a thickness of 4.0 mm, the Co/C composite showed the lowest reflection loss of −33.45 dB when the initial mass ratio of cobalt nitrate and SC was 1:1. The effective absorbing bandwidth (EAB) could achieve 3.5 GHz at 2 mm thickness. This work not only opens up a new avenue for the facile fabrication of dielectric and magnetic loss combinations and their structural design, but it also creates a new route for the high value-added exploitation of SC.
研究领域:
材料科学
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能源与环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yishuai Fu,Wenliang Wang,Hui Miao,Yangyi Cui,Yutong Chen,Ziwei Wang,Guowei Xiao,Bailiang Xue,Weikun Jiang
Obtaining key platform chemicals from lignin is a sustainable refining concept of the non-petroleum route. Rapid pyrolysis is a potential refining technology, and microwave-assisted catalytic depolymerization with low energy consumption is preferred. Herein, we reported the strategy of microwave-initiated depolymerization using a self-designed dynamic vapor flow reaction system with a facilely prepared CMF@Co-MoS 2 -0.18 catalyst, achieving efficient conversion of lignin (Dealkalize) to monophenol. Under constant microwave irradiation (2.45 GHz), the CMF@Co-MoS 2 -0.18 catalyst had excellent dielectric properties (Dielectric loss factor: 0.56) and microwave heating properties (∼140 s rise to ∼ 600℃). Therefore, microwave-initiated depolymerization of lignin showed that the CMF@Co-MoS 2 -0.18 catalyst can improve the monophenol content (54.72 %) and phenol selectivity (35.84 %) under the synergistic effect of microwave absorptivity and catalysis. The reaction of the lignin model and kinetics analysis show that the CMF@Co-MoS 2 -0.18 catalyst increases the yield of monophenol by reducing depolymerization activation energy and selectively breaking the β -O-4 bond. The finite element analysis pointed out that under microwave irradiation, CMF@Co-MoS 2 -0.18 continuously conducted heat to lignin and the lignin vapor would have sufficient energy to collide with the catalyst active site at a high frequency, which led to an increase in the pre-exponential factor and initiated catalytic depolymerization lignin. In summary, we provide a potential pathway for the rapid conversion of lignin into key platform chemicals.
研究领域:
化学工程
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可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Yajie Cheng,Zichen Xu,Qiang Wang,Kexin Zhang,Lin Wang,Yongbo Deng,Teng Ma,Hao Wei,Zengxian Guo
To address the issues of high filler content and poor wave absorption performance in single-component absorbers, we constructed tubular high-dielectric polypyrrole (PPy) through morphology control and doping, achieving high-performance microwave absorption at ultra-low filler content. This study utilized various surfactants for the oxidative polymerization of high-dielectric PPy (PPy-S X ) and its micromorphology was further optimized via pH regulation to further obtain excellent impedance matching of PPy (PPy-S 5 -X). Experimental results reveal that non-ionic surfactants, particularly methyl orange (MO), significantly improve the dielectric properties of tubular PPy (PPy-S 5 ). pH-regulation (from pH 1 to 11) markedly influences micromorphology. PPy-S 5 –5 (pH=5.0) possesses the most remarkable nanoparticle-nanotube morphology for impedance matching at ultralow filling content. With a thickness of 2 mm, PPy-S 5 –5 (5 wt% filling amount) exhibits an RL min of –40.88 dB with an effective absorption bandwidth of 5.04 GHz (10.24–15.28 GHz). By contrast, the RL min of PPy-S 5 –5 is over six times better than that of PPy-S 1 synthesized using cetyltrimethyl ammonium bromide (CTAB). This superior microwave absorption performance is due to enhanced electromagnetic wave loss for two main reasons: First, MO as a soft template promotes tubular PPy formation, allowing charges to continuously move and transfer between molecules to enhance conduction loss. Additionally, pH regulation optimizes particle distribution on PPy nanotubes, improving multi-interface interactions and interfacial polarization. This micromorphology regulation strategy of PPy unlocks its potential as a lightweight, efficient absorbent material, achieving superior absorption performance at low filling volumes in wave-absorbing applications.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
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2024
·
IF 8.3
Siyu Guo,Yanzhi Cai,Laifei Cheng,Yibing Yuan,Yuhan Wang,Haiming Yu,Zhongyi Hu,Dengpeng Chen,Hudie Yuan
Metal–organic frameworks (MOFs) have attracted attention due to their designable structures. However, recently reported MOF microwave-absorbing materials (MAMs) are dominated by powders. It remains a challenge to design MOF/carbon nanotube (CNT) composite structures that combine the mechanical properties of self-supporting flexibility with excellent microwave absorption. This work involves the hydrothermal approach to grow Ni-MOF of different microstructures in situ on the CNT monofilament by adjusting the molar ratio of nickel ions to organic ligands. Subsequently, an ultraflexible self-supporting Ni-MOF/CNT buckypaper (BP) is obtained by directional gas pressure filtration technology. The BP porous skeleton and the Ni-MOF with a unique porous structure provide effective impedance matching. The CNTs contribute to the conduction loss, the cross-scale heterogeneous interface generated by Ni-MOF/CNT BP provides rich interfacial polarization loss, and the porous structure complicates the microwave propagation path. All factors work together to give Ni-MOF/CNT BP an excellent microwave absorption capacity. The minimum reflection losses of Ni-MOF/CNT BPs decorated with granular-, hollow porous prism-, and porous prism-shaped Ni-MOFs reach −50.8, −57.8, and −43.3 dB, respectively. The corresponding effective absorption bandwidths are 4.5, 6.3, and 4.8 GHz, respectively. Furthermore, BPs show remarkable flexibility as they can be wound hundreds of times around a glass rod with a diameter of 4 mm without structural damage. This work presents a new concept for creating ultraflexible self-supported MOF-based MAMs with hierarchical interpenetrating porous structures, with potential application advantages in the field of flexible electronics.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2020
·Vol. 10
·期 4
·598
·
IF 4.324
Congai Han,Haiyan Zhang,Danfeng Zhang,Yunfei Deng,Junyao Shen,Guoxun Zeng
The reasonable design of magnetic carbon-based composites is of great significance to improving the microwave absorption (MA) performance of the absorber. In this work, ultrafine FeNi3nanocrystals (5–7 nm) embedded in a 3D honeycomb-like carbon matrix (FeNi3@C) were synthesized via a facile strategy that included a drying and carbonization process. Because of the soft magnetic property of the FeNi3nanocrystals and their unique 3D honeycomb-like structure, the FeNi3@C composites exhibit excellent MA abilities. When the filler loading ratio of FeNi3@C/paraffin composites is only 30 wt%, the maximum reflection loss (RL) value is −40.6 dB at 10.04 GHz. Meanwhile, an ultra-wide absorption frequency bandwidth of 13.0 GHz (5.0–18.0 GHz over −10 dB) can be obtained in the thickness range of 2.0–4.5 mm, and this means that the absorber can consume 90% of the incident waves. It benefits from the dual loss components, multiple polarizations, and multiple reflections for improving MA performances of FeNi3@C composites. These observations suggest that the 3D honeycomb-like FeNi3@C composites have broad application prospects in exploring new MA materials that have a wide frequency bandwidth and strong absorption.Keywords:FeNi3@C composites;3D honeycomb-like carbon;microwave absorption
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 26
·11970-11983
·
IF 3.553
Niu Yingchun,Li Xueai,Dong Wenqi,Zhang Can,Zhao Kuihu,Wang Fengyan,Wang Haiyan
Carbon and iron composites have drawn much attention for their unique electromagnetic properties. In addition, nitrogen doping of carbon can effectively modulate the dielectric properties of carbon. Therefore, synthesis of N-doped carbon and iron composites is an alternative method for obtaining high-efficiency microwave absorption materials. In previous studies, the synthesis process was very complicated including multistep routes. In this work, N-doped carbon with embedded Fe/Fe 3 C was synthesized in-situ via pyrolysis of amino phenol formaldehyde resin (APF) scattered with Fe 2 O 3 nanoparticles (APF/Fe 2 O 3 ), which was obtained through a simple hydrothermal process. During the heat-treatment process, the APF resin was converted into N-doped carbon, and simultaneously, the Fe 2 O 3 was reduced to iron nanoparticles. Then, inevitably, the iron nanoparticles reacted with carbon to form Fe 3 C at the interface between the iron particles and carbon. Taking advantage of multiple heterogenous interface, the interfacial polarization relaxation could be enhanced. Therefore, the N-doped carbon with embedded Fe/Fe 3 C particles displays microwave absorption with a maximum reflection loss of − 70 dB. Moreover, the effective absorption bandwidth (reflection loss of less than − 10 dB) reaches 6.02 GHz at a thickness of 2.13 mm. This study not only provides composites of N-doped carbon with embedded Fe/Fe 3 C particles with excellent stable microwave absorption but also offers a simple method for synthesizing N-doped carbon with embedded Fe/Fe 3 C particles.
研究领域:
材料科学
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电磁学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2020
·Vol. 13
·期 23
·5331
·
IF 3.057
Yue Yuan,Shicheng Wei,Yi Liang,Bo Wang,Yujiang Wang
Cobalt ferrite is synthesized via a simple solvothermal method. Then, the effect of the degree of cobalt-ferrite growth on its morphology, structure, electromagnetic performance, and microwave absorption is studied as a function of the solvothermal reaction time. When the reaction time during synthesis is 8 h, the structure of cobalt ferrite is hollow spheres. In addition, when the reaction time is 12 h and 16 h, it becomes a submicron sphere with a diameter of 100–150 nm. With the increase of reaction time, cobalt ferrite underwent the process of cobalt ferrite formation, hollow structure formation, hollow structure disappearance, agglomeration separation and reagglomeration in 4–16 h. In general, CoFe2O4-8h shows better microwave absorption-the effective absorption bandwidth is 9.84 GHz (6–15.84 GHz) for a thickness of 1.72–3.72 mm. This represents a minimum return loss of −47.24 dB. A better understanding of both the synthesis parameters and the relationship between structure and electromagnetic properties can open new possibilities for applications and the development of microwave absorbing materials.Keywords:cobalt ferrite;reaction time;structure;microwave absorption properties
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2019
·
IF 6.309
Qixin Yang,Yiyuan Shi,Yu Fang,Yubing Dong,Qingqing Ni,Yaofeng Zhu,Yaqin Fu
A novel ternary nanocomposite of Fe 3 O 4 functionalized porous biomass carbon decorated by aligned polyaniline (A-PANI/Fe 3 O 4 /PBC) was successfully fabricated by hydrothermal and in situ oxidative polymerization. The morphology and structure of the composite was characterized by X-ray diffraction, fourier transform infrared spectra, scanning electron microcopy, transmission electron microscopy , X-ray photoelectron spectra and vibrating sample magnetometer . The microwave absorbing properties of A-PANI/Fe 3 O 4 /PBC composite were investigated in the frequency of 2–18 GHz. The results indicated that the A-PANI/Fe 3 O 4 /PBC composite possess excellent microwave absorbing performance, and the minimum reflection loss can be up to −44.8 dB at 10.67 GHz, effective absorbing bandwidth ( RL < −10 dB) reaches 4.69 GHz with a thickness of 2.7 mm. The excellent microwave absorbing performance of composite was mainly related to the multi-loss mechanisms, good impedance matching, synergistic and geometrical effect of porous biomass carbon, magnetic particles and aligned PANI.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2021
·Vol. 27
·期 1
·135
·
IF 4.412
Zhengwei Qu,Yi Wang,Pingan Yang,Wei Zheng,Nan Li,Jingying Bai,Youwei Zhang,Kailin Li,Dashuang Wang,Zhaohui Liu,Kexin Yao,Rui Li,Yuxin Zhang
In this work, spherical flower-shaped composite carbonyl iron powder@MnO2(CIP@MnO2) with CIP as the core and ultrathin MnO2nanosheets as the shell was successfully prepared by a simple redox reaction to improve oxidation resistance and electromagnetic wave absorption properties. The microwave-absorbing properties of CIP@MnO2composites with different filling ratios (mass fractions of 20%, 40%, and 60% after mixing with paraffin) were tested and analyzed. The experimental results show that compared with pure CIP, the CIP@MnO2composites have smaller minimum reflection loss and a wider effective absorption bandwidth than CIP (RL < −20 dB). The sample filled with 40 wt% has the best comprehensive performance, the minimum reflection loss is −63.87 dB at 6.32 GHz, and the effective absorption bandwidth (RL < −20 dB) reaches 7.28 GHz in the range of 5.92 GHz–9.28 GHz and 11.2 GHz–15.12 GHz, which covers most C and X bands. Such excellent microwave absorption performance of the spherical flower-like CIP@MnO2composites is attributed to the combined effect of multiple beneficial components and the electromagnetic attenuation ability generated by the special spherical flower-like structure. Furthermore, this spherical flower-like core–shell shape aids in the creation of discontinuous networks, which improve microwave incidence dispersion, polarize more interfacial charges, and allow electromagnetic wave absorption. In theory, this research could lead to a simple and efficient process for producing spherical flower-shaped CIP@MnO2composites with high absorption, a wide band, and oxidation resistance for a wide range of applications.Keywords:spherical flower-like structure;CIP@MnO2;microwave absorption;interfacial polarization
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）