Facile preparation, high microwave absorption and microwave absorbing mechanism of RGO–Fe3O4 composites

Abstract

The reduced graphene oxide (RGO)/Fe 3 O 4 composites with an obviously enhanced microwave absorption property had been successfully fabricated by rational one-pot simplified co-precipitation route, which avoided the usage of inert gas and any additional chemical agents (such as surfactants and stabilizer).Given these advantages, the strategy described in this study can be developed as a simple and large-scale yield route to RGO/Fe 3 O 4 composites. The morphology, structure, thermal stability, magnetic and microwave electromagnetic properties of as-prepared composites were characterized by XRD, XPS, TEM, FT-IR, Raman, TG and VSM. Those composites exhibit excellent microwave absorption properties, which are attributed to effective complementarities between the dielectric loss and the magnetic loss. The microwave absorption mechanism of the RGO/Fe 3 O 4 composites was studied in detail. For RGO/Fe 3 O 4 -3 composite, the maximum R L reaches -44.6 dB at 6.6 GHz with a thickness of 3.9 mm, and the bandwidth of RL less than -10 dB can reach up to 4.3 GHz (from 12.2 to 16.5 GHz) with a thickness of 2.0 mm. Moreover, the microwave absorption property can be tuned easily by varying the (RGO)/(Fe 3 O 4 ) ratio and layer thickness of the samples. It is believed that such composites will find their wide applications in microwave absorbing area.-2 -expanded EM interference problems. 3-5 They can absorb microwaves effectively and convert EM energy into thermal energy or make microwaves dissipated by interference. The microwave absorbing materials are now requested to have strong absorption characteristics, wide absorption frequency, lightweight and antioxidation. 4 There are a number of microwave absorbing materials such as ferrites, carbonyl iron, conducting polymers and carbon-based materials etc. 6-9 However, the traditional microwave absorbing materials can not meet all of the requirements such as strong, wide, lightweight and thin at the same time.Hence, extensive studies have been made to develop novel microwave absorping materials with high absorption and wide absorption frequency.Graphene, a novel carbon nanomaterial consisting of one-atom-thick, hexagonally arranged carbon atoms, has attracted extensive attention owing to its superior electronic, thermal and mechanical properties as well as its chemical stability. 10,11 Due to its special surface properties and layered structure, graphene becomes potential nanoscale building blocks for new hybrid materials. 12 Recent research shows that inorganic nanoparticles, such as Au, Ag, Fe 3 O 4 and Co 3 O 4 , etc., could be attached to graphene or graphene oxide (GO) to form hybrid materials, which have potential applications in surface enhanced Raman scattering (SERS), lithium ion batteries, hydrogen storage, microwave absorption and magnetic resonance imaging (MRI) contrast agent, etc.. [13][14][15][16] As a class of promising microwave absorping materials, carbon-based materials exhibited several exceptional properties including lightweight, wide absorption frequency, high...

Economical synthesis of composites of FeNi alloy nanoparticles evenly dispersed in two-dimensional reduced graphene oxide as thin and effective electromagnetic wave absorbers

“…This may be due to the reason that the xed quantity of Fe 3+ and Ni 2+ ions is dispatched to the increasing number of GO sheets, thus leading to the decrease in the average density of FeNi particles. 43 Moreover, the average particle sizes of FeNi alloy (Fig. 2g-i) are 17.23, 18.90 and 21.04 nm, respectively, indicating that the diameters of FeNi nanoparticles increase with the increasing amount of GO.…”

A Simple and Scalable Method for the Preparation of Magnetite/Graphene Oxide Nanocomposites under Mild Conditions

“…Graphenebased composites are then obtained by transformation of GO to reduced graphene oxide (RGO). Extensive literature survey reveals three general synthesis routes for the formation of magnetic graphene particles: hydrothermal (more broadly and solvothermal) approaches [13][14][15][16][17][18][19][20][21], direct pyrolysis [9,11,22], and coprecipitation [23][24][25][26][27][28][29][30], all of which rely on in situ crystallization of MNPs on the carbonaceous layers and usually lead to the simultaneous reduction of GO to RGO.…”

Graphene Nanocomposites for Electromagnetic Induction Shielding

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