Salt-assisted pyrolysis of carbon nanosheet and carbon nanoparticle hybrids for efficient microwave absorption

Metal-organic framework MOF-derived carbon materials are considered high potential candidates for electromagnetic wave absorbers. However, the rational design of MOF-derived microwave absorbing (MA) materials with stable structures and ultra-wide effective absorption bandwidth (EAB) is still challenging. Herein, a strategy for salt-assisted pyrolysis of MOFs is proposed to construct a 3D hybrid nanostructure comprising carbon nanoparticles and carbon nanosheets. The three-dimensional structure was adjusted by varying the type and proportion of salt, where NC-KCl exhibited the best microwave absorption performance, with an RLmin value of -40.58 dB and an EAB value of 6.24 GHz at a lower fill rate (7%). Numerical simulation results demonstrate that 3D hybrid nanostructures of nanoparticles and nanosheets outperform isolated nanoparticle structures in terms of interfacial polarization and conductivity loss. This work proposes a new strategy to provide a practical guide for optimizing the absorption properties of MOF-derived carbon MA materials.