Porous Fe₃O₄/Carbon Core/Shell Nanorods: Synthesis and Electromagnetic Properties

Abstract

The porous Fe 3 O 4 /carbon core/shell nanorods were fabricated via a three-step process. R-Fe 2 O 3 nanorods were first obtained, and R-Fe 2 O 3 /carbon core/shell nanorods were subsequently fabricated using glucose as a carbon source by a hydrothermal method, in which the thickness of the carbon coating was about 3.5 nm. Fe 3 O 4 /carbon core/shell nanorods were synthesized after an annealing treatment of the product above under a mixture of Ar/H 2 flow. After the H 2 deoxidation process, the Fe 3 O 4 core exhibited a character of porosity; the thickness of the carbon shell was decreased to about 2.5 nm, and its degree of graphitization was enhanced. The interesting core/ shell nanostructures are ferromagnetic at room temperature, and the Verwey temperature was about 120 K. Electromagnetic properties of the core/shell nanorodÀwax composite were investigated in detail. The maximum reflection loss was about À27.9 dB at 14.96 GHz for the composite with a thickness of 2.0 mm, and the absorption bandwidth with the reflection loss below À18 dB was up to 10.5 GHz for the absorber with the thickness of 2À5 mm. The excellent electromagnetic wave absorption properties of the porous Fe 3 O 4 /carbon core/shell nanorods were attributed to effective complementarities between the dielectric loss and the magnetic loss.

Synthesis and Potential Adsorption of Fe3O4@C Core-Shell Nanoparticles for to Removal of Pollutants in Aqueous Solutions: A Brief Review.

“…These characteristics depend on the phases of iron oxide used, which can be magnetite (Fe 3 O 4 ) [29,[32][33][34], hematite (α-Fe 2 O 3 ) [35][36][37], maghemite (γ-Fe 2 O 3 ) [38][39][40] and wustite (FeO) [41].…”

“…Depending on the synthesis techniques, a variety of scales and shapes can be synthesized, such as sphere, cube, prism, platelets, wire, rod, tube, etc. In order to synthesize Fe 3 O 4 @C core-shell nanostructures at different scales and shapes, several methodologies have been developed [34,37,[47][48][49][50][51][52][53][54][55].…”

“…Recently, Fe 3 O 4 @C core-shell has been developed at room temperature by applying a hydrothermal process consisting of three steps: at first, hematite (α-Fe 2 O 3 ) nano rods were obtained; α-Fe 2 O 3 @C core-shell nano rods were subsequently fabricated using glucose as a carbon source by a hydrothermal method; finally, Fe 3 O 4 @C core-shell were synthesized after an annealing treatment of the product from the previous stage under a flow of a Ar/H 2 mixture Figure 6: A precipitation stage of the oxide in alkali medium followed by a carbon coating. [37]. Iinterestingly, Fe 3 O 4 core has shown many pores whose mean diameter is about 12 nm and its shell exhibits an enhanced degree of graphitization [37].…”

“…[37]. Iinterestingly, Fe 3 O 4 core has shown many pores whose mean diameter is about 12 nm and its shell exhibits an enhanced degree of graphitization [37].…”

Strengthened electromagnetic absorption performance derived from synergistic effect of carbon nanotube hybrid with Co@C beads

“…As the development of new types of EM absorbers only by varying magnetic components and permeability is quite limited, much research attention has been directed towards finding innovative dielectric loss materials with low density and high loss performance. Among various kinds of dielectric loss materials, carbon materials have always been attractive due to their low density, abundant resources, and low cost [27][28][29]. In particular, carbon nanotubes have been regarded as one competitive candidate based on their good conductivity, strong mechanical property, and high aspect ratio.…”