MOF-Derived\nPorous Co/C Nanocomposites with Excellent\nElectromagnetic Wave Absorption Properties

Abstract

Composites\nincorporating ferromagnetic metal nanopartices into\na highly porous carbon matrix are promising as electromagnetic wave\nabsorption materials. Such special composite nanomaterials are potentially\nprepared by the thermal decomposition of metal–organic framework\n(MOF) materials under controlled atmospheres. In this study, using\nCo-based MOFs (Co-MOF, ZIF-67) as an example, the feasibility of this\nsynthetic strategy was demonstrated by the successful fabrication\nof porous Co/C composite nanomaterials. The atmosphere and temperature\nfor the thermal decomposition of MOF precursors were crucial factors\nfor the formation of the ferromagnetic metal nanopartices and carbon\nmatrix in the porous Co/C composites. Among the three Co/C composites\nobtained at different temperatures, Co/C-500 obtained at 500 °C\nexhibited the best performance for electromagnetic wave absorption.\nIn particular, the maximum reflection loss (RL) of Co/C-500 reached\n−35.3 dB, and the effective absorption bandwidth (RL ≤\n−10 dB) was 5.80 GHz (8.40 GHz–14.20 GHz) corresponding\nto an absorber thickness of 2.5 mm. Such excellent electromagnetic\nwave absorption properties are ascribed to the synergetic effects\nbetween the highly porous structure and multiple components, which\nsignificantly improved impedance matching.