The impact of RGO and MWCNT/RGO on the microwave absorption of NiFe2O4@Fe3O4 in the presence or absence of PANI

Abstract

This study investigates the impact of 1D (MWCNT) and 2D (RGO) carbonaceous structures on the microwave absorption performance of NiFe₂O₄@Fe₃O₄ nanocomposites decorated with/without PANI. These nanocomposites were fabricated using hydrothermal, coprecipitation, and in situ polymerization methods, resulting in various morphologies. The absorbers feature core@shell structures, 1D nanotubes, and 2D reduced graphene oxide layers, coated with polyaniline. These components contribute to quad-band absorption in the S, C, X, and Ku bands, with a maximum effective absorption bandwidth of 4.8 GHz for S₇ at a matching thickness of only d = 1.6 mm. The optimal reflection loss for S₅ reaches RL_min of −47.5 dB at 4.6 GHz with a matching thickness of 4.6 mm, showing its best EAB of 4 GHz for d = 1.6 mm. Additionally, CST simulation software demonstrates that the prepared materials effectively dissipate microwave energy in practical use. The impressive reflection loss and quad-band absorption are a result of the synergetic effects of various factors, such as core@shell structures, heterogeneous interfaces, multidimensional structures, and created defects. Analysis using the Smith chart confirmed the excellent impedance matching properties and strong electromagnetic wave attenuation of the conductive network of PANI/MWCNT/RGO, which collectively enhance the broadband absorption performance. The results of our study on MWCNT/graphene/polymer-based magneto-electric nanocomposite systems offer a promising foundation for the development of lightweight, high-performance microwave-absorbing materials with potential practical applications.