Magnetic Carbon Composites Derived from Coal Hydrogasification Residue for Microwave Absorption

Abstract

To cut the cost of microwave absorption materials (MAMs) and achieve the recycling of semicoke (SC), the by‐product in coal hydrogasification process, SC was applied to prepare composite MAMs. The facile synthesis process involves liquid‐phase impregnation, and then in situ carbothermal reduction treatment. Champion sample prepared under 800 °C (FeSC800) exhibits the minimum reflection loss (RLmin) of −39.3 dB under a coating thickness of 2.5 mm, and the effective absorption bandwidth (EAB) can reach 3.9 GHz (14.1–18 GHz) at a coating thickness of 1.5 mm. The enhancement of interfacial and dipole polarization, as well as the synergistic effect between the dielectric properties of SC matrix and the magnetic properties of Fe particles, can account for the excellent microwave absorption (MA) performance. In view of the source of SC matrix, the prepared FeSC800 was not only expected to become a candidate in the field of MAMs, but also presented a promising approach for the resource utilization of SC.