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MOF-derived yolk–shell Ni/C architectures assembled with Ni@C core–shell nanoparticles for lightweight microwave absorbents
CrystEngComm ( IF 2.6 ) Pub Date : 2020-09-17 , DOI: 10.1039/d0ce01242d
Xiaolei Wang 1, 2, 3, 4 , Qiyao Geng 1, 2, 3, 4 , Guimei Shi 1, 2, 3, 4 , Yajing Zhang 4, 5, 6, 7 , Da Li 4, 8, 9, 10, 11
Affiliation  

Yolk–shell Ni/C microspheres composed of Ni@C core–shell nanoparticles were successfully fabricated by decomposing a Ni-based metal–organic framework (Ni-MOF) at 500 °C and 600 °C. The Ni-MOF with a yolk–shell structure was prepared by a solvothermal method with an appropriate molar ratio of Ni(NO3)2·6H2O to C9H6O6 in the presence of PVP. The degree of crystallization of Ni and C was improved by increasing the pyrolysis temperature, which resulted in enhanced complex permittivity and optimized impedance matching of Ni/C microspheres for damping microwave. Meanwhile, the attenuation coefficient of Ni/C microspheres increased with the increment in pyrolysis temperature. The yolk–shell Ni/C microspheres obtained at 600 °C exhibited the optimal reflection loss (RL) reaching −39 dB with a bandwidth of 3.8 GHz (RL < −10 dB) at a thin matching thickness of 1.8 mm. The integrated bandwidth can achieve 12.3 GHz covering Ku-band (12–18 GHz), X-band (8–12 GHz), and most of C-band (5.7–8 GHz) with an appropriate thickness of 1.4–3.9 mm. Such excellent microwave absorption performance can be attributed to the synergistic effect of the magnetic and dielectric losses of Ni/C microspheres due to natural resonance, dipolar polarization and multiple interfacial polarizations at a unique yolk–shell interface, achieving the optimization of impedance matching and microwave attenuation. This work demonstrates that Ni/C microspheres with a desirable yolk–shell structure are potential candidates for the application in microwave absorption field.

中文翻译:

MOF派生的卵黄壳Ni / C结构与Ni @ C核壳纳米颗粒组装而成,用于轻质微波吸收剂

通过在500°C和600°C下分解基于Ni的金属-有机骨架(Ni-MOF),成功制造了由Ni @ C核壳纳米粒子组成的卵黄壳Ni / C微球。通过溶剂热法以适当的摩尔比Ni(NO 32 ·6H 2 O与C 9 H 6 O 6制备具有卵黄壳结构的Ni-MOF。在PVP的情况下。通过提高热解温度可以改善Ni和C的结晶度,从而提高复介电常数,并优化用于阻尼微波的Ni / C微球的阻抗匹配。同时,Ni / C微球的衰减系数随着热解温度的升高而增加。在600°C时获得的蛋黄壳Ni / C微球表现出最佳反射损耗(RL)达到-39 dB,带宽为3.8 GHz(RL <-10 dB),匹配厚度为1.8 mm。集成带宽可以达到12.3 GHz,覆盖Ku波段(12–18 GHz),X波段(8–12 GHz)和大部分C波段(5.7–8 GHz),且厚度为1.4–3.9 mm。如此出色的微波吸收性能可以归因于Ni / C微球的磁和介电损耗的协同效应,这是由于独特的卵黄-壳界面处的自然共振,偶极极化和多种界面极化所致,从而实现了阻抗匹配和微波的优化衰减。这项工作表明,具有理想卵黄壳结构的Ni / C微球是在微波吸收领域中应用的潜在候选者。
更新日期:2020-10-06
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