Boosted Interfacial Polarization from the Multidimensional Core–Shell–Flat Heterostructure CNP@PDA@GO/rGO for Enhanced Microwave Absorption

Abstract

Heterogeneous structures have attracted extensive attention in the area of microwave absorption because they can promote interfacial polarization and thus enhance microwave absorption. Many efforts have been made in this field; however, challenges remain in terms of the absorber impedance matching and electromagnetic (EM) wave reflectivity. Herein, a multidimensional core−shell−flat heterostructure is proposed to build a kind of EM wave absorbers with both dielectric loss and magnetic loss. Polydopamine (PDA) is coated on the surface of nanoscale carbonyl nickel powder (CNP) to obtain the core−shell structure of CNP@PDA nanoparticles, and then, the CNP@PDA nanoparticles are grafted around graphene oxide (GO)/reduced GO (rGO) or sandwiched between the layers of GO/rGO to form a core−shell−flat heterostructure. Two-dimensional GO/rGO and three-dimensional PDA can modulate the impedance matching of nano-CNP and enhance the interfacial polarization of the absorber. The reflection loss of ternary CNP@PDA@GO/rGO is better than that of binary CNP@PDA or CNP@GO due to the interfacial polarization and multiple interfacial scattering of the heterostructure. The minimum reflection loss can reach −70.7 dB with a thickness of 2.5 mm, while the efficient absorption bandwidth (≤−10 dB) can achieve 8.5 GHz. The heterojunction contacts constructed by CNP−PDA and PDA−GO/rGO contribute to the enhanced polarization loss and interfacial reflection loss. The mechanism of excellent EM wave absorption is explained by enhanced interfacial polarization, interface scattering, and adjusted impedance matching. These results pave the way to fabricate high-performance EM wave absorption materials with a controlled multidimensional morphology and balanced impedance matching.

Reduced graphene oxide-wrapped Fe–Fe3O4@mSiO2 hollow core–shell composites with enhanced electromagnetic wave absorption properties

“…This conducting network disperses the electrostatic charges and thereby brings about intense conductivity loss. 32,33…”

“…This conducting network disperses the electrostatic charges and thereby brings about intense conductivity loss. 32,33 The dielectric loss of FFmSR was further analyzed according to the Debye relaxation theory. 34 Each Debye semicircle, namely a section of the e 0 -e 00 curve that presents a semicircular shape, represents Debye relaxation, while a straight line segment in the e 0 -e 00 curve is related to the conduction loss.…”

Cuttlebone‐Derived Interfacial Solar Evaporators for Long‐Term Desalination and Water Harvesting

“…[28] Moreover, the PDA coating can absorb most incident light over the whole solar spectrum and quickly convert solar energy into heat. [29] Then, the cuttlebone@PDA/rGO was prepared by coating the cuttlebone@PDA with rGO via reaction between the imino groups of PDA and the active groups of GO (e.g., carboxyl and epoxy), [30] and then partial reduction of GO. The dark brown cuttlebone@PDA/rGO was uniformly covered by rGO and exhibited apparent metallic luster (Figure 1b).…”