Self-Assembled Heterojunction Interfaces between g-C3N4 and rGO Nanosheets for Enhanced Electromagnetic Wave Absorption

Graphene has been widely used in the field of electromagnetic wave (EMW) absorption because it has many excellent properties, such as excellent electrical conductivity, large specific surface area, and good mechanical properties. However, the high conductivity and single loss mechanism lead to poor impedance matching and microwave absorption performance. Herein, we developed a strategy to introduce g-C3N4 nanosheet to combine with graphene oxide (GO) to enhance the heterojunction interfaces, thus bringing abundant interfacial polarization loss. Moreover, the excessive electrons on GO can be transferred to g-C3N4 through the electrostatic interaction between the g-C3N4 and GO layers. And on this basis, we designed g-C3N4-rGO into an aerogel structure to endow the material with a plentiful porous structure, which promotes the reflection and scattering of electromagnetic waves. In addition, the electromagnetic parameters of the material are adjusted by controlling the weight ratio of g-C3N4 and GO, as well as the calcination temperatures, to obtain a material with both excellent impedance matching and microwave absorbing properties. As a result, the synthesized aerogel shows remarkable EMW absorption performance with a broad effective absorption bandwidth (EAB) of 8.08 GHz and a reflection loss (RL) of −38.08 dB. To sum up, this work provides inspiration and guidance for designing nanomaterials with both outstanding impedance matching and microwave absorption performance.