Chiffon cake-derived hierarchically porous carbon with efficient microwave absorption properties

In this work, hierarchically porous carbons were synthesized by carbonizing chiffon cake at different carbonization temperature from 600 to 1200 °C. The synthesis method exhibits that bio-derived food waste is more nature-friendly as no external hazardous activators are used during the pyrolysis process, and it takes less cost. The corresponding microwave absorption properties were proved to be dependent on the carbonization temperature, as well as resulting crystal structures and graphitization degrees. With the carbonization temperature of 1000 °C, the obtained samples (C1000) showed excellent microwave absorption performance with a maximum reflection loss − 49.52 dB at 17.7 GHz. The broad effective absorption bandwidth reached 5.1 GHz (12.4–17.5 GHz) at the thickness of 1.52 mm. The optimal absorbing property can be attributed to the strong dielectric loss, good impedance matching and quarter-wavelength cancellation. This work provides a way to prepare low cost, green and sustainable microwave absorbent with efficient microwave absorption property.