Enhanced Microwave Absorption by incorporating Fe_3O_4 nanoparticles into Ordered Mesoporous Carbon

摘要

Novel Fe_3O_4/ordered mesoporous carbon (OMC) composite powders have been prepared by impregnation and reduction methods for the microwave absorbing application purpose. The Fe_3O_4 nanoparticles were encapsulated in the mesopores of OMCs, and Fe_3O_4 contents in the composite could be easily controlled by changing the concentration of ferric nitrate solution during the preparation. The Fe_3O_4/OMC composites show very excellent microwave absorbing properties with respect to pure OMC samples, in a frequency ranging of 8.2-12.4 GHz. A minimum reflection loss (RL) value of -32 dB at 11.35 GHz and a broader absorption band with the RL values under -10 dB are obtained when the thickness of samples is 1.6 mm. The enhanced microwave absorption of the Fe_3O_4/OMC nanocomposites is contributed to the better impedance match between dielectric loss and magnetic loss, which originates from the incorporation of magnetic species into OMC.