Precisely reducing the size of metal-organic frameworks (MOFs) derivatives is an effective strategy to manipulate their phase engineering owing to size-dependent oxidation; however, the underlying relationship between the size of derivatives and phase engineering has not been clarified so far. Herein, a spatial confined growth strategy is proposed to encapsulate small-size MOFs derivatives into hollow carbon nanocages. It realizes that the hollow cavity shows a significant spatial confinement effect on the size of confined MOFs crystals and subsequently affects the dielectric polarization due to the phase hybridization with tunable coherent interfaces and heterojunctions owing to size-dependent oxidation motion, yielding to satisfied microwave attenuation with an optimal reflection loss of -50.6 dB and effective bandwidth of 6.6 GHz. Meanwhile, the effect of phase hybridization on dielectric polarization is deeply visualized, and the simulated calculation and electron holograms demonstrate that dielectric polarization is shown to be dominant dissipation mechanism in determining microwave absorption. This spatial confined growth strategy provides a versatile methodology for manipulating the size of MOFs derivatives and the understanding of size-dependent oxidation-induced phase hybridization offers a precise inspiration in optimizing dielectric polarization and microwave attenuation in theory. 

/pdf/size-dependent-oxidation-induced-phase-engineering-for-mofs-3j1yz2gj.pdf

Size-Dependent Oxidation-Induced Phase Engineering for MOFs Derivatives Via Spatial Confinement Strategy Toward Enhanced Microwave Absorption

Developing ultrabroad radar-infrared compatible stealth materials has turned into a research hotspot, which is still a problem to be solved. Herein, the copper sulfide wrapped by reduced graphene oxide to obtain three-dimensional (3D) porous network composite aerogels (CuS@rGO) were synthesized via thermal reduction ways (hydrothermal, ascorbic acid reduction) and freeze-drying strategy. It was discovered that the phase components (rGO and CuS phases) and micro/nano structure (microporous and nanosheet) were well-modified by modulating the additive amounts of CuS and changing the reduction ways, which resulted in the variation of the pore structure, defects, complex permittivity, microwave absorption, radar cross section (RCS) reduction value and infrared (IR) emissivity. Notably, the obtained CuS@rGO aerogels with a single dielectric loss type can achieve an ultrabroad bandwidth of 8.44 GHz at 2.8 mm with the low filler content of 6 wt% by a hydrothermal method. Besides, the composite aerogel via the ascorbic acid reduction realizes the minimum reflection loss (RLmin) of - 60.3 dB with the lower filler content of 2 wt%. The RCS reduction value can reach 53.3 dB m2, which effectively reduces the probability of the target being detected by the radar detector. Furthermore, the laminated porous architecture and multicomponent endowed composite aerogels with thermal insulation and IR stealth versatility. Thus, this work offers a facile method to design and develop porous rGO-based composite aerogel absorbers with radar-IR compatible stealth. 

https://link.springer.com/content/pdf/10.1007/s40820-022-00906-5.pdf

Ultrabroad Microwave Absorption Ability and Infrared Stealth Property of Nano-Micro CuS@rGO Lightweight Aerogels

/pdf/ultrabroad-microwave-absorption-ability-and-infrared-stealth-1gl15dww.pdf

MoS2 wrapped MOF-derived N-doped carbon nanocomposite with wideband electromagnetic wave absorption

A Dual-Band Transceiver with Excellent Heat Insulation Property for Microwave Absorption and Low Infrared Emissivity Compatibility

Hierarchical engineering of suitable dielectric‐magnetic multicomponents shows good performance for microwave absorbers, but still face bottlenecks. Herein, hierarchical double‐shelled nanotubes (DSNTs), in which the inner magnetic tubular subunits are assembled by magnetic‐heteroatomic components through cation‐exchange reactions, and the outer dielectric MnO2 nanosheets strengthen the synergistic interactions between confined heterogeneous interfaces are ingeniously designed and constructed. Hetero‐interfaces induced polarization is proposed to investigate the interfacial relaxation mechanism, and magnetic loss, closely related to the micrometer‐scale magnetic units, is mainly clarified by the magnetic interaction composed of magnetic coupling and magnetic diffraction; both of them are clearly confirmed by Lorentz off‐axis electron holography. The obtained hierarchical DSNTs demonstrate efficient microwave absorption with an optimal reflection loss of −54.7 dB and qualified absorption bandwidth of 9.5 GHz owing to desirable heterogeneous interfaces, multiple magnetic heteroatomic components and hollow hierarchical microstructures. This strategy inspires a generalized methodology for the engineering of hollow hierarchical configurations with multishells, the combination of proposed hetero‐interfaces induced polarization and microscale magnetic interaction broadens the dielectric‐magnetic synergistic mechanism of the topography–performance relationship for microwave absorption materials.

Hierarchical Engineering of Double‐Shelled Nanotubes toward Hetero‐Interfaces Induced Polarization and Microscale Magnetic Interaction

Electrospinning of Hierarchical Carbon Fibers with Multi-Dimensional Magnetic Configurations Toward Prominent Microwave Absorption

Heterointerface engineering is evolving as an effective approach to tune electromagnetic functional materials, but the mechanisms of heterointerfaces on microwave absorption (MA) remain unclear. In this work, abundant electromagnetic heterointerfaces are customized in multilevel hollow architecture via a one‐step synergistic polymerizing‐etching strategy. Fe/Fe3O4@C spindle‐on‐tube structures are transformed from FeOOH@polydopamine precursors by a controllable reduction process. The impressive electromagnetic heterostructures are realized on the Fe/Fe3O4@C hollow spindle arrays and induce strong interfacial polarization. The highly dispersive Fe/Fe3O4 nanoparticles within spindles build multi‐dimension magnetic networks, which enhance the interaction with incident microwaves and reinforce magnetic loss capacity. Moreover, the hierarchically hollow structure and electromagnetic synergistic components are conducive to the impedance matching between absorbing materials and air medium. Furthermore, the mechanisms of electromagnetic heterointerfaces on the MA are systematically investigated. Accordingly, the as‐prepared hierarchical Fe/Fe3O4@C microtubes exhibit remarkable MA performance with a maximum refection loss of −55.4 dB and an absorption bandwidth of 4.2 GHz. Therefore, in this study, the authors not only demonstrate a synergistic strategy to design multilevel hollow architecture, but also provide a fundamental guide in heterointerface engineering of highly efficient electromagnetic functional materials.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/advs.202200804

Customizing Heterointerfaces in Multilevel Hollow Architecture Constructed by Magnetic Spindle Arrays Using the Polymerizing‐Etching Strategy for Boosting Microwave Absorption

Pan-deng Liu

Papers

Hierarchical Engineering of Double‐Shelled Nanotubes toward Hetero‐Interfaces Induced Polarization and Microscale Magnetic Interaction

Size-Dependent Oxidation-Induced Phase Engineering for MOFs Derivatives Via Spatial Confinement Strategy Toward Enhanced Microwave Absorption

Electrospinning of Hierarchical Carbon Fibers with Multi-Dimensional Magnetic Configurations Toward Prominent Microwave Absorption

Customizing Heterointerfaces in Multilevel Hollow Architecture Constructed by Magnetic Spindle Arrays Using the Polymerizing‐Etching Strategy for Boosting Microwave Absorption

Hierarchical design of FeCo-based microchains for enhanced microwave absorption in C band