Electromagnetic Wave Absorption Properties of Reduced Graphene Oxide Modified by Maghemite Colloidal Nanoparticle Clusters

Abstract

Graphene is highly desirable as an electromagnetic wave (EM) absorber because of its large interface, high dielectric loss, and low density. Nevertheless, the conductive and electromagnetic parameters of pure graphene are too high to meet the requirement of impedance match, which results in strong reflection and weak absorption. In this paper, we report a facile solvothermal route to synthesize reduced graphene oxide (RGO) nanosheets combined with surface-modified γ-Fe 2 O 3 colloidal nanoparticle clusters. The obtained two-dimensional hybrids exhibit a relatively low EM reflection coefficient (RC) and wide effective absorption bandwidth, which are mainly attributed to the unique microstructure of colloidal nanoparticle clusters assembled on RGO. The nanoparticle clusters have more interfaces. The interfacial polarization within nanoparticle clusters and conductivity loss of RGO plays an important role in absorbing EM power. The minimum RC reaches −59.65 dB at 10.09 GHz with a matching thickness of 2.5 mm. The special integration of some metal oxide semiconductor crystals assembled on RGO sheets provides an effective avenue to design metal oxide semiconductor/carbon hybrids as EM absorbing materials.

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

“…1,9,30 Meanwhile, the abundant functional groups and defects residing on the sheets of rGO render to this material modest electric conductivity and optimistic polarization as a potential EM wave absorber. 31 To satisfy the impedance matching conditions, magnetic/rGO-based composites have been investigated to pursue an improved microwave absorption capability. For example, Zeng et al synthesized the hollow reduced graphene oxide microspheres embedded with Co nanoparticles by a simple and efficient two-step method.…”

Broadening Electromagnetic Absorption Bandwidth: Design from Microscopic Dielectric‐Magnetic Coupled Absorbers to Macroscopic Patterns

“…[20,30,31] Initially, the commercial graphite sample 500 mg was treated in mixing solution of water and EtOH for stirring and sonication for 20 h. Upon the samples were dried, the as-treated powders were then added into an acidic mixing solution (HNO 3 :H 2 SO 4 ¼ 1:3 in volume ratio), followed by sonication for 2 days. Until the liquid exfoliation was completed, the mixture was then transferred to 3 L water, followed by washing abundant water.…”

“…[13][14][15][16][17][18][19] In the recent study on the carbonbased hybrid fillers, carbon nanotube and graphene nanostructures, mostly reduced graphene oxide (RGO), are more attractive because the sp2 hybridized carbon structure not only provides effective pathways for electromagnetic energy loss, but offers the active site for chemically bonding heterostructures or hetero-atoms in tuning electromagnetic parameters. [20][21][22] In typical examples, Bai and co-workers used polyethylene oxide as the both dispersion agents and matrices in the fabrication of polymeric RGO composites, which show a strong absorption peak around À38.8 dB and an effective absorption bandwidth (the bandwidth with absorption intensity <À10 dB) from 14 to 18 GHz in the investigation range. [23] Later, Che and Peng have utilized the carbon nanotube arrays to demonstrate that the aligned carbon nanotubes are able to achieve variable absorption capability via tuning the direction of the nanotube arrays.…”

Carbon nanostructure composite for electromagnetic interference shielding

“…Kong et al [110] used reduced GO sheet modified with γ -Fe 2 O 3 colloidal nanoparticle clusters. The interfacial polarization in the magnetic clusters and loss of conductivity in reduced GO contribute in the absorption-dominant shielding mechanism which was explained using resistor capacitor circuit model.…”