Facile synthesis of hollow cube-like ZnSnO3 wrapped by nitrogen-doped graphene: As a high-performance and enhanced synergistic microwave absorber

In recent years, high-efficiency absorption properties, low filler loading and lightweight of microwave absorbing materials have received increased attention in the field of electromagnetic wave absorption. Herein, hollow ZnSnO₃ nanocrystals grown on nitrogen-doped graphene nanosheets (ZnSnO₃-NRGO) has been successfully synthesized through a simple hydrothermal route. As a synergistic microwave absorber, ZnSnO₃-NRGO exhibits remarkable microwave absorbing performances compared with ZnSnO₃. The maximum reflection loss (R_Lmax) of ZnSnO₃-NRGO (with low filler loading ration of only 10 wt%) can reach up to −40.8 dB at 17.6 GHz with an absorber thickness of only 2 mm and the efficient absorption bandwidth (R_L exceeding −10 dB) is 3.2 GHz. Under the thickness of 3 mm, the R_Lmax of ZnSnO₃-NRGO can reach −33.2 dB at 13.7 GHz with high-efficiency bandwidth (R_L < −10 dB) of 6.4 GHz (from 11.4 to 18 GHz). The improving performances can be attributed to more reasonable impedance matching, higher attenuation capability, proper synergistic effect and multiple interfacial polarizations. Therefore, this work demonstrates that ZnSnO₃-NRGO with light-weight and strong microwave absorption performance shows the great potential as a microwave absorber.