MOF decomposed for the preparation of Co3O4/N-doped carbon with excellent microwave absorption

Bai, Yi-Wen; Shi, Guimei; Gao, Jun; Shi, Fa‐Nian

doi:10.1016/j.jssc.2020.121401

Cited by 52 publications

(13 citation statements)

References 47 publications

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“…When the thickness was 2.0 mm, it could achieve effective absorption in the range from 7.40 to 8.80 GHz, showing excellent microwave absorption performance. The RL min value was shifted to the low frequency zone with the increase in sample thickness, which also conformed to the quarter wavelength attenuation law. − In addition, the absorbing properties of samples S0–S3 increased with the increase in Ni@GNP loading. Interestingly, the RL min value of sample S4 (cf.…”

Section: Resultssupporting

confidence: 66%

Enhanced Thermally Conductive and Microwave Absorbing Properties of Polymethyl Methacrylate/Ni@GNP Nanocomposites

Yang

Jia

et al. 2021

Ind. Eng. Chem. Res.

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In this work, Ni@GNP nanohybrids fabricated via an in situ reduction method were incorporated into polymethyl methacrylate (PMMA) to prepare PMMA/Ni@GNP nanocomposites via solution blending and hot-pressing. The Ni nanoparticles with an average diameter of 70–80 nm were observed to successfully grow on the GNP surface via SEM and TEM. Both thermally conductive and microwave absorbing properties of the prepared composites were intensively investigated. A reflection loss test experimentally suggested that the PMMA/Ni@GNP composites showed a good microwave absorbing property, among which the composite containing 30 wt % Ni@GNP displayed the best microwave absorption performance (with a value of −30 dB for RL min in the C band). The thermal conduction behavior of the composites was jointly studied by infrared thermal imaging (ITI) and enthalpy transformation method together with a four-parameter model. The average heating rate during an initial stage was obviously found to increase from 65.4 to 103.2 °C/min, indicating that a well-defined heat conduction network gradually formed in the composites, which exerted positive influence on heat conduction. The composites generally bore perfect thermal conductivities (e.g., with a maximum in-plane thermal conductivity of 9.02 W/m·K and a maximum out-of-plane value of 1.29 W/m·K), and the variations of thermal conductivity versus filler loading should be attributed to the construction of an anisotropically thermally conductive network in the composites. The PMMA/Ni@GNP composites with desirable microwave absorption and thermal conductivity would find potential applications in 5G communication devices.

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Section: Resultssupporting

confidence: 66%

Enhanced Thermally Conductive and Microwave Absorbing Properties of Polymethyl Methacrylate/Ni@GNP Nanocomposites

Yang

Jia

et al. 2021

Ind. Eng. Chem. Res.

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“…However, cobalt introduction clearly alters the few top nanometers of the sup- respectively, 20,32 while the Co 3+ species usually appear at 780.0 eV or lower binding energies (a small shoulder in the XPS spectrum). [33][34][35][36][37][38][39][40][41][42][43] However, what is more important in this work is the amount of cobalt impregnated, since the next practical step in catalyst preparation would be reduction.…”

Section: Resultsmentioning

confidence: 99%

“…Both main peaks of Co 2p 3/2 and Co 2p 1/2 are indicative of Co 2+ and possibly Co 3+ species. The components with a binding energy of 781.0 and 783.3 eV can be assigned to Co 2+ in CoO and Co(OH) 2 , respectively, 20,32 while the Co 3+ species usually appear at 780.0 eV or lower binding energies (a small shoulder in the XPS spectrum) 33–43 . However, what is more important in this work is the amount of cobalt impregnated, since the next practical step in catalyst preparation would be reduction.…”

Section: Resultsmentioning

confidence: 99%

XPS characterization of cobalt impregnated SiO₂ and γ‐Al₂O₃

Cañón

Teplyakov

2021

Surface & Interface Analysis

111

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SiO2 and γ‐Al2O3 impregnation with nominal 10 and 20% of cobalt was examined using wet impregnation method starting with Co(NO3)2·6H2O. The samples were dried and analyzed by XPS prior to calcination to study the surface species in the solids and the role of the support in the processing of supported cobalt catalysts. The results showed that cobalt introduction alters the few top nanometers of the support materials as there are significant changes recorded in the XPS spectra. Most importantly, there is a remarkable similarity between the O 1s XPS signal of SiO2 and γ‐Al2O3 following Co 20% impregnation, which suggests that these materials could have similar properties in terms of the oxidation ability and the general redox behavior. The shift of Al 2p peaks to higher binding energy (BE) in the XPS investigations and the shift of Si 2p peaks to lower BE were observed for high nominal cobalt loading. These results suggest that the choice of the support in cobalt‐based catalysts would tune the chemical characteristics of cobalt in the final materials.

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“… 52 Besides, Bai et al fabricated stratiform Co 3 O 4 /N-doped carbon using a Co-based MOF as the precursor. 127 The optimal RL of the samples reached −42.63 dB with the thickness of only 1.5 mm. Besides the above metal oxides/PC composites, some similar composites and other certain elements derived materials like ZrO 2 /C, 128 TiO 2 /C 129 and CoO/Co/C 130 are listed in Table 4 .…”

Section: Mof-derived Pc Materials For Microwave Absorptionmentioning

confidence: 88%

Recent progress of MOF-derived porous carbon materials for microwave absorption

Tong

et al. 2021

RSC Adv.

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MOF decomposed for the preparation of Co3O4/N-doped carbon with excellent microwave absorption

Cited by 52 publications

References 47 publications

Enhanced Thermally Conductive and Microwave Absorbing Properties of Polymethyl Methacrylate/Ni@GNP Nanocomposites

Enhanced Thermally Conductive and Microwave Absorbing Properties of Polymethyl Methacrylate/Ni@GNP Nanocomposites

XPS characterization of cobalt impregnated SiO₂ and γ‐Al₂O₃

Recent progress of MOF-derived porous carbon materials for microwave absorption

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MOF decomposed for the preparation of Co3O4/N-doped carbon with excellent microwave absorption

Cited by 52 publications

References 47 publications

Enhanced Thermally Conductive and Microwave Absorbing Properties of Polymethyl Methacrylate/Ni@GNP Nanocomposites

Enhanced Thermally Conductive and Microwave Absorbing Properties of Polymethyl Methacrylate/Ni@GNP Nanocomposites

XPS characterization of cobalt impregnated SiO2 and γ‐Al2O3

Recent progress of MOF-derived porous carbon materials for microwave absorption

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XPS characterization of cobalt impregnated SiO₂ and γ‐Al₂O₃