Facile fabrication of Fe/Fe₃C@starch-derived hierarchical porous carbon for microwave absorption

The three-dimensional (3D) porous carbon materials are helpful for forming thin, light-weight, wide effective absorption bandwidth and strong absorption intensity absorbers. However, previous methods were not environmentally friendly enough. Thus, in this work, the Fe/Fe₃C@porous carbon was synthesized from soluble starch and Fe(NO₃)₃·9H₂O via chemical bowling and subsequent carbonization at 700 °C with different ratios. When the ratio of starch to Fe(NO₃)₃·9H₂O is 1:1.5, the porous carbon exhibits a strong absorption ability with minimum reflection loss (RL_min) value of −16.64 dB at 16.78 GHz, when the thickness is 1.75 mm and the proportion of paraffin wax is 30 wt%. The synergy of well impedance matching, sufficient loss performance, and interface polarization makes 3D porous carbon materials an excellent wave absorber. This work provides a good inspiration for studying outstanding performance microwave absorption materials.