Graphitic carbon nitride nanosheets for microwave absorption

In this study, we have demonstrated for the first time that the graphitic carbon nitride (g-C3N4) nano-sheets can possess interesting microwave absorption performance. A large reflection loss (RL) value of -36.1 dB has been demonstrated, corresponding to absorption efficiency over 99.9%. Meanwhile, we have also elucidated the independent contributions of the permittivity and permeability to the microwave absorption. Without the contribution of the electrical or magnetic relaxations, the microwave absorption efficiency decreases. Specifically, the microwave absorption performance decreases much faster without the contribution of the magnetic relaxation than without the contribution of the electrical relaxation. Therefore, the magnetic relaxation in g-C3N4 nanosheets has a large role in their microwave absorption. The origins of those relaxations can be traced back to the dipole rotation and magnetic domain resonance inside the materials. In addition, we have also proposed a macroscopic interference model for the microwave absorption behavior of the g-C3N4 nanosheets, so that the frequency to reach maximum RL can be precisely predicted given the thickness of the g-C3N4 nanosheet absorber. (C) 2018 Elsevier Ltd. All rights reserved.