Enhanced microwave absorption properties of N-doped ordered mesoporous carbon plated with metal Co

We demonstrate an excellent performance of nitrogen-doped ordered mesoporous carbon (NOMC) plated with metal cobalt for microwave absorption in the frequency range of 2-18 GHz. Spherical NOMC particles with a cubic Im3(_)m symmetry are synthesized by organic-organic self-assembly of triblock copolymer, 3-aminophenol and hexamethylenetetramine (HMTA) in basic aqueous solution. The prepared NOMC particles possess uniform mesopores, a high specific surface area and a considerable N-doped amount. An electroless plating method is established to deposit cobalt layer on the surface of NOMC particles. Benefiting from the unique dielectric property of NOMC and magnetic property of metal Co, the resultant Co/NOMC composite shows an excellent microwave reflection loss (R.L.) performance. Particularly in Ku waveband, the R.L. can reach −30 dB with lower thickness than 1.6 mm, and wide effective bandwidth (R.L. ≤ −10 dB) can be obtained. The R.L. values below −15 dB can be achieved in the whole measuring frequency range by adjusting the absorber thickness. These results indicate that the Co/NOMC composite can become a promising candidate for lightweight microwave absorbing materials in a wide frequency range.