Facile synthesis of Al substituted Cu-ferrite infused reduced graphene oxide (rGO) nanohybrid for improving microwave absorption at gigahertz frequencies

This work mainly deals with the synthesis of Al substituted copper ferrite infused reduced graphene oxide (rGO) as a microwave absorbing material in a frequency ranging from 8.2 to 12.4 GHz (X-band). Firstly, Al substituted copper ferrite (CAF) infused rGO was synthesized using the solvothermal method. Then it mixed in the epoxy media to fabricate lightweight nanocomposites for their potential uses as competent electromagnetic wave absorbers. The structural analysis using XRD validates the successful substitution of Al into copper ferrite lattice. TEM results showed that copper-Al-ferrite's spherical morphology with size similar to 20-30 nm is well infused on rGO in the as-synthesized nanohybrid. BET analysis confirmed numerous pore formations in the nanohybrid that created during CAF over rGO. Furthermore, the effect of rGO-loaded/and unloaded nanohybrid on the microwave absorption properties was also studied. Notably, it is seen that the strategy to infuse CAF on rGO was found more effective in enhancing the absorption capacity of pure CAF. Remarkably, the CAF-rGO/epoxy nanocomposite exhibited excellent microwave absorption capacity as the reflection loss (RL) value of - 35.7 dB (99.973% absorption) is achieved with 3.55 GHz of broad - 10 dB (90% absorption) bandwidths under the low filler content of 20 wt% and small matching thickness of 2.2 mm. Besides, the possible microwave absorption mechanisms in the nanohybrid composite are also disclosed. Therefore, our results could be helpful to manufacture the rGO based dielectric-magnetic hybrid nano composites for the highly efficient and lightweight microwave absorber exclusively for X band application, i.e., in the high gigahertz range. (C) 2022 Elsevier B.V. All rights reserved.