Almond C/FexOy composite material based on biomass porous carbon structure with high-efficiency microwave absorbing properties

As a carrier of stealth technology and electromagnetic protection, microwave absorbing materials have received extensive attention from researchers. Herein, a biomass porous C/FexOy composite was prepared by heat treatment of almond shell layers dipped in different concentrations of iron nitrate solution at 600 °C, 800 °C, and 1000 °C, respectively. The composite material was examined and found to have good microwave absorption properties and multi-loss synergistic effects. When the ferric nitrate concentration is 22.3%, and the heat treatment temperature is 800 °C, the minimum reflection loss can be obtained as − 31.8 dB with a thickness of 2.5 mm. The frequency bandwidth with a reflection loss of less than − 10 dB is 4.80 GHz when the absorber thickness is 2 mm. Therefore, almond wood porous biomass carbon exhibits strong microwave absorbing properties and has great application potential in military and civilian fields.