Metal-organic frameworks derived porous hollow Co/C microcubes with improved synergistic effect for high-efficiency microwave absorption

Abstract High-performance microwave absorption materials with strong absorption and thin thickness have increasingly become a reach hotspot. Here, we successfully prepared a novel porous hollow Co/C microcube by controlling the pyrolysis of the Co-based metal-organic frameworks (MOFs) precursor. The phase composition, microstructure, porosity, and magnetic properties were well modified by controlling the pyrolysis temperature. The multiple components (Co and C) and novel porous structure endowed Co/C microcubes with efficient microwave absorption. As expected, the porous hollow Co/C microcubes achieved enhanced microwave absorption with a strong reflection loss of −52.8 dB, a wide effective absorbing bandwidth of 4.5 GHz, and an ultra-thin thickness of 1.4 mm. It was found that the underlying microwave absorption mechanism was the dielectric loss stemmed from the interfacial polarization, magnetic loss caused by the magnetic resonance, and multiple reflections and scattering in the porous structure. Thus, this work can provide a facile method to develop the MOFs-derived porous hollow composites with high-efficiency microwave absorption performance.