Heterostructure design of Ni/C/porous carbon nanosheet composite for enhancing the electromagnetic wave absorption

The development of advanced electromagnetic wave (EMW) materials with high reflection loss (R-L), wide effective absorption bandwidth (EAB), low filler loading and thin matching thickness is considered as an effective strategy to solve the EMW pollution in emerging areas. Nevertheless, it is still a tremendous challenge to design a reasonable structure and a proper composition to meet the requirements of advanced absorbing materials. Herein, a nanocomposite composed of nitrogen-doped (N-doped) biomass-derived carbon (BDC) and Ni/C nanosphere derived from Ni-MOF (MPC@Ni/C) has been designed and synthesized. The results show that the continuous conductive network can not only improve the conductive loss, but also provide the prospect for the reflection and scattering of EMW. Also, the petal-like MPC@Ni/C nanocomposite with a great quantity defects and heterogeneous interfaces delivers multi-polarization. At the same time, the ultra-small Ni nanoparticles and Ni/C nanospheres with good dispersion on carbon materials are beneficial toward dielectric-magnetic combination, resulting in impedance matching. Accordingly, the optimized MPC@Ni/C nanocomposite exhibits extraordinary microwave absorption performance. Precisely, when the filler loading is 20 wt%, the maximum R-L of MPC@Ni/C reaches -73.8 dB and a corresponding EAB is up to 5.8 GHz with 2.2 mm thickness. This work fills the vacuum in the study of the nanocomposites composed of MOF derivatives and BDC. It provides a reference value for the synthetic strategies in designing high-performance absorbing materials. (C) 2021 Elsevier Ltd. All rights reserved.