Metal‐Organic Framework Derived Hierarchical Co/C@V₂O₃ Hollow Spheres as a Thin, Lightweight, and High‐Efficiency Electromagnetic Wave Absorber

Abstract

Developing high‐efficiency electromagnetic (EM) wave absorbing materials with light weight, thin thickness, and wide absorption bandwidth is highly desirable for ever‐developing electronic and telecommunication devices. Herein, hierarchical metal–organic framework (MOF)‐derived Co/C@V2O3 hollow spheres were designed and synthesized through a facile hydrothermal, precipitation, and pyrolysis method. The composite exhibits both excellent impedance matching and light weight due to the rational combination of hollow V2O3 spheres and porous Co/C. Additionally, multiple components enable a large dielectric and magnetic loss of the composite, giving rise to enhanced EM wave absorption performance with a maximum reflection loss (RL) of −40.1 dB and a broad effective absorption bandwidth (RL < −10 dB) of 4.64 GHz at a small thickness of 1.5 mm. This work provides insights into the design of hierarchical hollow and porous composites as thin and lightweight EM wave absorbers with efficient absorption, which can also be extended to energy storage, catalysis, and sensing.

Carbon-Based MOF Derivatives: Emerging Efficient Electromagnetic Wave Absorption Agents

“…The coating thickness TiO 2 shell affected the impedance matching condition to enhance the EMW absorption performance, and it could protect the Co core from oxidizing as well. Similarly, Zhou et al prepared hierarchical Co/C@V 2 O 3 hollow spheres by pyrolyzing V 2 O 3 coated ZIF-67, which exhibited the EMW performances with a minimum RL value of − 40.1 dB at the matching thickness of 1.5 mm, corresponding to an EAB of 4.64 GHz [ 146 ]. Liang et al further developed a core–shell structure of ZnO/nanoporous carbon@Co/nanoporous carbon (ZnO/NPC@Co/NPC) by the pyrolysis of ZIF-8@ZIF-67 precursor [ 147 ].…”

Sandwich-Like Fe&TiO2@C Nanocomposites Derived from MXene/Fe-MOFs Hybrids for Electromagnetic Absorption

“…The magnetic particles could be derived from novel metal organic framework (MOFs) materials [38][39][40][41]. Owing to their unique porous structures, MOFs are considered as ideal precursors for preparing nanostructured metal@C nanocomposites through facile heat treatment methods and provide intriguing electromagnetic (EM) absorption properties [42][43][44][45]. For instance, Zhou et al [44] fabricated hierarchical MOF-derived Co/C@V 2 O 3 hollow spheres with an enhanced EMW absorption performance (RL min of − 40.1 dB and EBW of 4.64 GHz at a thickness of 1.5 mm).…”

“…Owing to their unique porous structures, MOFs are considered as ideal precursors for preparing nanostructured metal@C nanocomposites through facile heat treatment methods and provide intriguing electromagnetic (EM) absorption properties [42][43][44][45]. For instance, Zhou et al [44] fabricated hierarchical MOF-derived Co/C@V 2 O 3 hollow spheres with an enhanced EMW absorption performance (RL min of − 40.1 dB and EBW of 4.64 GHz at a thickness of 1.5 mm). Liu et al [46] synthesized porous carbon-wrapped Ni composites from Ni-based MOF with high EMW absorption performance (RL min of − 51.8 dB and an EBW of 3.48 GHz at a thickness of 2.6 mm).…”

Rational Construction of Hierarchically Porous Fe–Co/N-Doped Carbon/rGO Composites for Broadband Microwave Absorption

“…Recently, metal–organic frameworks (MOFs) have attracted wide attention due to their unique structures [ 25 , 26 ]. The Co-MOF-derived Co/C composites have the advantages of low density, nanoporous structure, multiple polarization centers, and the coexistence of magnetic loss and dielectric loss, which are beneficial to improve the impedance matching and multiple reflection and scattering of microwaves.…”