High-Yield Two-Dimensional Metal–Organic Framework Derivatives for Wideband Electromagnetic Wave Absorption

Abstract

Two-dimensional metal−organic frameworks (2D-MOFs) and their derivatives are promising for catalysis, energy storage, gas separation, etc. due to their unique microstructure and physicochemical properties. Many efforts have been devoted to fabricating 2D-MOFs with challenges remaining in yield and fine control of their thickness and lateral size. Here a versatile strategy has been used involving epitaxial, anisotropic, and confined growth of CoNi-MOF-71 nanosheet arrays, giving rise to excellent quantity and controllability of the 2D-MOFs. Electromagnetic (EM) wave absorption performance has been investigated for the resultant 2D Co/Ni/C derivatives. Compared with the bulk counterpart, significantly increased surface area, conductivity, and shape anisotropy for the 2D derivatives result in enhanced interfacial polarization, conductive loss, and magnetic resonance. As such, optimum EM wave absorption of minimum reflection loss RL min = −49.8 dB and an ultrawide effective adsorption bandwidth EAB = 7.6 GHz can be achieved at a thickness of 2.6 mm. This work not only sheds light on the performance enhancement for 2D absorbers via synergistic effects of multiple attenuation mechanisms but also provides an effective fabrication route of ultrathin MOFs with high yield and uniform size for extended applications in catalysis, electrochemistry, and optoelectronics fields.

Construction of 1D Heterostructure NiCo@C/ZnO Nanorod with Enhanced Microwave Absorption

“…7, we can get the relationship between | | Z in ∕Z 0 | | and frequency of different samples. Generally, the closer the | | Z in ∕Z 0 | | value of the EMW-absorbing material is to 1, the EMW materials will absorb EM more easily [66], and the absorbing material will show better EMW absorption performance. From Fig.…”

Ni Flower/MXene-Melamine Foam Derived 3D Magnetic/Conductive Networks for Ultra-Efficient Microwave Absorption and Infrared Stealth

“…S3a). Generally, the eddy current effect could be evaluated according to the C 0 value [ 43 ]. The calculation formula of the C 0 value was as follows: …”

State of the Art and Prospects in Metal-Organic Framework-Derived Microwave Absorption Materials

“…Therefore, the anisotropic magnetic materials such as thin film, flat plate and wire are worth trying to construct MAMs with high performance. For instant, Liu and co-workers synthesized porous Co/Ni/C nanosheets with CoNi-MOF-71 as precursors [ 76 ]. The Co/Ni/C nanosheets exhibited enhanced magnetic loss due to the great shape anisotropy of 2D Co/Ni, which provided higher coercivity and natural resonance frequency because of the break of Snoek’s limit.…”

“…Natural resonance is generated by the intrinsic anisotropic field of the MAM. The natural resonance linewidth is related to damping coefficient [ 67 , 75 , 76 ]. The natural resonance frequency is represented by Eq.…”