# Graphene and Iron Reinforced Polymer Composite Electromagnetic Shielding Applications: A Review
## 4 Graphene-Based Composites
### Graphene@Iron Composites
#### 4.1.2 Interpretation of Graphene@Iron Composites Articles  
Different types of graphene such as pristine graphene, reduced graphene oxide, and graphene oxide have been investigated for EMI shielding alone and at times as a combination with other materials which possess conductive and magnetic properties [46; 78; 79; 80]. Being a 2D nanomaterial, graphene has remarkable electrical properties that is why it has  
Figure 5: Iron component types. been used extensively for EMI shielding. With iron and graphene combinations researchers introduce a third material to enhance their properties such as epoxy, polymer, silicon dioxide (SiO\({}_{2}\)), titanium dioxide (TiO\({}_{2}\)) etc. The work is still going on with different formed combination to deliver quality results. [PERSON] et al. [81] used a hydrothermal method to fabricate hollow ZnFe\({}_{2}\)O\({}_{4}\) microspheres@graphene which was decorated with TiO\({}_{2}\) nanosheets. The highest reflection loss of ZnFe\({}_{2}\)O\({}_{4}\)@graphene@TiO\({}_{2}\) with the coating of 2.5 mm was up to \(-\)55.6 dB at 3.8 GHz, where the absorbing bandwidth surpassing \(-\)10 dB at 6.4 GHz with the same thickness. The results prove that ZnFe\({}_{2}\)O\({}_{4}\)@graphene@TiO\({}_{2}\) provides good absorption in low frequency. [PERSON] et al. [82] conducted a study on low frequency microwaves using the Pechini sol-gel method, where a new microwave absorber material was synthesized having the combination of reduced graphene oxide which was covered with Fe@\({}_{\gamma}\)-Fe\({}_{2}\)O\({}_{3}\) and Fe/Co/Ni. It was revealed that the microwave absorption efficiency (0.4 MHz-20 GHz) comes in the range of 60%-100% by using these materials, depending on the metallic particles' nature grafted on reduced graphene oxide. [PERSON] et al. [83] adopted a scalable copecipitation process to form aerogels exhibiting strong electromagnetic wave absorption material using cellulose/reduced graphene oxide and Fe\({}_{3}\)O\({}_{4}\) with the loading of 8 wt.% and 15 wt.%. With the aerogel thickness of 0.5 mm, 32.4-40.1 dB EMI shielding effectiveness was achieved for 8.2-12.4 GHz frequency. The shielding effectiveness got higher by introducing a larger amount of reduced graphene oxide with loading varies between 3-8 wt.% and increasing the thickness between 0.5-2 mm. Shielding effectiveness reached 49.4-52.4 dB with 2 mm sample thickness. It was concluded that high shielding effectiveness can be achieved with the help of lightweight aerogels. [PERSON] et al. [84] utilized a solvothermal method to synthesize the NiFe\({}_{2}\)O\({}_{4}\) nanoparticles with reduced graphene oxide to observed EMI shielding performance within the frequency range of 8.2-12.4 GHz. Significant dielectric and magnetic loss were shown by the nanocomposite compared to RGO with improvement in electromagnetic wave absorption. With 2 mm thickness, the shielding effectiveness of 38.2 dB at 10.8 GHz was achieved with a  
Figure 6: Keyword Analysis of Graphene@Iron-based composites articles. 35/65 ratio of NiFe\({}_{2}\)O\({}_{4}\)/RGO. [PERSON] et al. [85] decorated magnetic CoFe\({}_{2}\)O\({}_{4}\) nanoparticles on MoS\({}_{2}\)-reduced graphene oxide surface using hydrothermal method. The EMI shielding effectiveness was examined within the range of 8.0-12.0 GHz, where the pure MoS\({}_{2}\)-RGO nanocomposite gives shielding effectiveness of 16.52 dB while the MoS\({}_{2}\)-RGO/CoFe\({}_{2}\)O\({}_{4}\) nanocomposite provides shielding effectiveness of 19.26 dB. [PERSON] et al. [64] used a facile solvothermal method for developing a magnetic Fe\({}_{3}\)O\({}_{4}\) combined with graphene nanoplates by constructing spherical Fe\({}_{3}\)O\({}_{4}\) particles with integrity crystal on the graphene sheet surface.