Fe₃O₄@Carbon@Polyaniline Trilaminar Core–Shell Composites as Superior Microwave Absorber in Shielding of Electromagnetic Pollution

Abstract

The present work reports fabrication of trilaminar core–shell composites of Fe3O4@C@PANI as efficient lightweight electromagnetic wave absorber by facile hydrothermal method and subsequent high-temperature calcination followed by its encapsulation through oxidative polymerization of aniline. The prepared composite structure was characterized by FTIR, XRD, XPS, TEM, HRTEM, and SQUID. The measurement of reflection loss, complex permittivity, complex permeability, and total shielding efficiency of the composites has been carried out in the frequency range of 2–8 GHz. Our findings showed lowest reflection loss (∼33 dB) in composite comprised of Fe3O4@C:aniline (1:9 wt/wt) corresponding to shielding efficiency predominantly due to absorption (∼47 dB) than reflection (∼15 dB). Such high value of shielding efficiency could be ascribed to the presence of dual interfaces and dielectric–magnetic integration in Fe3O4@C@PANI. In all probability, higher dielectric loss through interface polarization and relaxation effects in Fe3O4@C@PANI could also contribute toward superior microwave absorption ability of Fe3O4@C@PANI compared to Fe3O4@C and Fe3O4/PANI binary composites. This is likely to enhance the interfacial polarization, natural resonance, dielectric polarization, trapping of EM waves by internal reflection, and effective anisotropy energy in Fe3O4@C@PANI.

Selective and Recyclable Congo Red Dye Adsorption by Spherical Fe3O4 Nanoparticles Functionalized with 1,2,4,5-Benzenetetracarboxylic Acid

“…The characteristic absorption bands for Fe 3 O 4 material appear at 585, 635, 1405, 1625, and 3426 cm −1 , whereas, for Fe 3 O 4 @BTCA material, bands appear at 585, 635, 1385, 1491, 1581, 1625, 3426 cm −1 . The common peaks at 585 and 635 cm −1 can be assigned to Fe-O bond vibrations 52 , while broad absorption bands appearing at 1625, 1405, and 3426 cm −1 arise due to O-H bond vibration of water molecules [53][54][55] adsorbed on the surface of both materials. The appearance of additional peaks at 1385, 1491 and 1581 cm −1 in the case of Fe 3 O 4 @BTCA indicates the presence of BTCA group.…”

Improved Electrochemical Performance of FeF3 by Inlaying in a Nitrogen‐Doped Carbon Matrix

“…The binding energy of about 286.3 eV was assigned to C=O bonds. [60][61][62][63] The FeF 3 content in the composites were measured by TG-DSC (Figure 3c). [29,37,44] The XPS results indicate that the N atoms were successfully doped into carbon in the form of pyrrolic N. 43 Many characterizations were conducted to analyze the samples.…”

“…The particular peak (1230 cm À 1 ) in FCN is considered to be derived from CÀ N stretching vibrations, which imply the nitrogen atoms were doped into the carbon skeleton. [60][61][62][63] The FeF 3 content in the composites were measured by TG-DSC ( Figure 3c). Exothermic peaks at 400°C are considered to be caused by the oxidation of FeF 3 to Fe 2 O 3 .…”

Dopamine-derived cavities/Fe3O4 nanoparticles-encapsulated carbonaceous composites with self-generated three-dimensional network structure as an excellent microwave absorber

“…3(a). The diffraction peaks in all tested composites are 29 It should be pointed out that no other impurity peaks were detected in the patterns and the phase purity can be clearly conrmed. The structural changes in the carbon framework were further investigated using Raman spectra ( Fig.…”