Metal Ions Confined in Periodic Pores of MOFs to Embed Single‐Metal Atoms within Hierarchically Porous Carbon Nanoflowers for High‐Performance Electromagnetic Wave Absorption

Abstract

Nanocarbons with single-metal atoms (M-SAs) have displayed considerable potential in various fields of application due to high free energy of M-SAs and strong metal-support interaction. However, the uniform dispersion of M-SAs within the whole carbon matrix still remains a great challenge. Herein, Ni-SAs are uniformly dispersed within hierarchically porous carbon nanoflowers (Ni-SA/HPCF) via a spatial confinement of Ni ions within the periodic pores in metal-organic frameworks (MOFs) with a subsequent carbonization process. The Ni-SA/HPCF with abundant mesopores and an ultrahigh surface area (1137.2 m 2 g −1 ) exhibits unexpected electromagnetic wave (EMW) absorption property with a minimal reflection loss of -53.2 dB and an effective absorption bandwidth of 5.0 GHz, while the filler ratio in the matrix is merely 10 wt.%. Density functional theory calculations and experimental results reveal that the uniformly dispersed Ni-SAs break local symmetry of the electronic structure and increase electrical conductivity of host carbon matrix, thereby enhancing the EMW absorption properties. In addition, the unique 3D hierarchical porous morphology boosts the impedance matching property, which synergistically improves the EMW absorption performance of the Ni-SA/HPCF. This study provides an efficient approach to uniformly disperse M-SAs within hierarchically porous nanocarbons for EMW absorption and other potential applications.

Multifunctional Organic–Inorganic Hybrid Perovskite Microcrystalline Engineering and Electromagnetic Response Switching Multi‐Band Devices

“…[8,9] High sensitivity, strong detectivity, broad response frequency, and excellent stability EM devices are urgently needed. [10][11][12][13][14][15] The update and iteration of electronic communication, material synthesis, EM response mechanism, and multifunctional integration technology have promoted the development of EM devices in the fields of sensing, detecting, energy storage, triboelectric nanogenerator, information transmission, Joule heating, microwave driving, etc. [16][17][18] For example, Li et al reported microwave-driven robots composed of wave-absorbing sheets and bimetallic sheets, which can realize path control by tuning the polarization direction of microwaves at 2.47 GHz.…”

Kinetics-mediated assembly assisted precise synthesis of magnetic ordered mesoporous carbon nanospheres for ultra-efficient electromagnetic wave absorption

“…9 and Table S2† for comparison. 31,57,58,62,92–99 Both Ni/OMCN-D and Ni/OMCN-S indeed possessed superior comprehensive EMWA performance to those similar EMWAMs in terms of RL max , EAB, thickness, and filler loading. Taking Ni/OMCN-D as an example, the associated mechanisms for the excellent EMWA performance mainly lied in the following aspects (Scheme 2).…”

A strategy based on composition control and structural design to prepare 3DOM RFCo composites with a 3D ordered macroporous structure for enhanced electromagnetic wave absorption

“…It can be seen that 3DOM RFCo-2 shows the best EMW absorption performance among all samples, and its EAB is up to 5.28 GHz, covering almost the whole Ku band (12-18 GHz), which is significantly better than those of similar existing materials (Table S1, ESI †). [10][11][12][27][28][29] In addition, to further investigate the 3DOM RFCo-2 composite, Fig. 4g shows a 2D RL plot of this material for a single thickness in the range of 1.5-5.0 mm and visualizes the maximum EAB and RL min values for different thicknesses.…”