Coupling between the 2D “Ligand” and 2D “Host” and Their Assembled Hierarchical Heterostructures for Electromagnetic Wave Absorption

Abstract

Constructing the strong interaction between the matrix and the active centers dominates the design of high-performance electromagnetic wave (EMW) absorption materials. However, the interaction-relevant absorption mechanism is still unclear, and the design of ultrahigh reflection loss (R L < −80 dB) absorbers remains a great challenge. Herein, CoFe-based Prussian blue (PB) nanocubes are coprecipitated on the surface of ultrathin CoAl-LDH nanoplates with the assistance of unsaturated coordination sites. During the subsequent pyrolysis process, CoAl-LDH serves as a “ligand” providing a Co source and reacts with Fe or C in the CoFe-PB “host” to form stable CoFe alloys or CoC x species. As a result, strong reactions emerged between the CoAl-LDH matrix and the active CoFe-CoC x @NC centers. Based on the experimental results, the CoAl/CoFe-CoC x @NC hierarchical heterostructure delivers good dielectric losses (dipolar polarization, interface polarization, and conductive loss), magnetic losses (eddy current loss, natural resonance, and exchange resonance), and impedance matching, resulting in a remarkable EMW absorption performance with a reflection loss (R L) value of −82.1 dB at a matching thickness of 3.8 mm. Theoretical results (commercial CST) identify that the strong interaction between the 2D CoAl-LDH “ligand” and 2D CoFe-CoC x “host” promotes a robust heterointerface among the nanoparticles, nanosheets, and nanoplates, which extremely contribute to the dielectric loss. Meanwhile, the coupling effect of nanosheets and nanoplates greatly contributes to the matching performance. This work provides an aggressive strategy for the effect of ligands and hosts on high-performance EMW absorption.

Self-Stacked Growth of Cu9S5 Nanostructures with Morphology Regulation as an Electromagnetic Wave Absorber

“…Previous works on semiconductor metal sulfides in the field of EM wave absorption have focused on MoS 2 , VS 2 , and WS 2 . − In the course of our research, we have shown that we can control the morphology of semiconductor Cu 9 S 5 nanomaterials by modulating the growth orientation of its crystals. Compared with previous studies, this work achieves the simultaneous optimization of absorber thickness, bandwidth, and reflection loss by introducing multiple loss mechanisms.…”

Adjacent Fe Site boosts electrocatalytic oxygen evolution at Co site in single-atom-catalyst through a dual-metal-site design

“…In addition, the [Fe(CN) 6 ] 3− in the electrolyte can chelate with the incompletely coordinated Co atom in the FeN 3 -CoN 2 S site on the surface of Co/Fe-SNC800, which can also contribute to the disappearance of the Co 2+ /Co 3+ redox peaks. 61–69…”

“…In addition, the [Fe(CN) 6 ] 3À in the electrolyte can chelate with the incompletely coordinated Co atom in the FeN 3 -CoN 2 S site on the surface of Co/Fe-SNC800, which can also contribute to the disappearance of the Co 2+ /Co 3+ redox peaks. [61][62][63][64][65][66][67][68][69] The previous results strongly indicated the electronic coupling between the Co and Fe sites from various aspects, which was further revealed in the microscopy investigations. Thus, the…”

Functional Tailoring of Multi‐Dimensional Pure MXene Nanostructures for Significantly Accelerated Electromagnetic Wave Absorption

“…[55] It can be observed that the tan 𝛿 𝜖 values of L-MXene and P-Mxene ML are larger than those of the other two samples (N-MXene NRs, P-MXene L) (Figure 4k). For EMW absorption, attenuation constant (𝛼 = [((2) 1/2 𝜋f)/c]/{(μ"𝜖"μ"𝜖") + [(μ"𝜖"μ"𝜖") 2 + (𝜖"μ" + 𝜖"μ") 2 ] 1/2 } 1/2 ), [56] eddy current (C 0 = μ"(μ′) −2 f −-1 = 2𝜋μ 0 d 2 𝜎), and impedance matching (Z = (μ r /𝜖 r ) 1/2 tanh|j2𝜋fd(μ r 𝜖 r ) 1/2 /c|) are important parameters to reveal the EMW absorption mechanism. Among them, 𝛼 represents the EMW attenuation ability.…”