Facile fabrication of carbon microspheres decorated with B(OH)3 and α-Fe2O3 nanoparticles: Superior microwave absorption

Abstract

We demonstrate that novel three-dimensional (3D) B(OH) and α-FeO nanoparticles decorated carbon microspheres (B(OH)/α-FeO-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1-3μm and decorated B(OH) and α-FeO nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)/α-FeO-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2-18GHz. They have a minimum reflection loss (RL) value of -52.69dB at a thickness of 3.0mm, and the effective absorption bandwidth for RL less than -10dB is as large as 5.64GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH) nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-FeO nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

Sustainable Low-Concentration Arsenite [As(III)] Removal in Single and Multicomponent Systems Using Hybrid Iron Oxide–Biochar Nanocomposite Adsorbents—A Mechanistic Study

“…The wide diffraction peaks at 26.5 and 44.7° correspond to the (002) and (100) planes of graphite (JCPDS card no. 41-1487). − These peaks correspond to a combination of carbon in sp 2 (26.5°; d spacing 3.35 Å) and sp 3 (44.7°; d spacing 2.06 Å) hybridization states. , The C (002) plane represents parallel and azimuthal orientation of the aromatic lamellae, while C (100) is indicative of the aromatic lamina size. Greater peak sharpness indicates a more aromatic lamellae formation and progressive aromatic ring condensation. , Other XRD peaks common to RHB, WHB, RHIOB, and WHIOB belonged to the mineral oxides present (SiO 2 , CaCO 3 , CaO, and MnO 2 ), often found in biochars.…”

“…Peaks at 24.2° (012), 25.5° (110), 33.1° (104), 54.4° (116), 64.0° (300), and 72.3° (119) are attributed to Fe 2 O 3 (maghemite) (JCPDS card no. 84-0310). ,, Two extra peaks observed at 31.8° (210) and 37.1° (21–2) could possibly belong to small amounts of FeOOH (goethite) (JCPDS card no. 34-1266). , …”

“…84-0310). 71,78,79 Two extra peaks observed at 31.8°(210) and 37.1°(21−2) could possibly belong to small amounts of FeOOH (goethite) (JCPDS card no. 34-1266).…”

Polyaniline Coated Core-Shell Typed Stimuli-Responsive Microspheres and Their Electrorheology

“…Ferric oxide (Fe 2 O 3 ) has been studied extensively in many applications, such as photocatalysis [87,88], wastewater treatment [89], biomedical [90], microwave absorption [91], sensors [92], and lithium-ion battery anodes [93]. A variety of Fe 2 O 3 structures, such as cube-shaped [94], rod-shaped [95], pine-leaf-shaped [96], and flower-like [97], have been fabricated successfully by different steps.…”

Synthesis and Electromagnetic and Microwave Absorption Properties of Monodispersive Fe3O4/α-Fe2O3 Composites

“…However, the microwave absorption performance of single-phase iron oxide is relatively weak, such as the impedance mismatching in the high-frequency of Fe 3 O 4 and the poor magnetic loss of α-Fe 2 O 3 . These problems can be effectively solved by constructing composites, such as α-Fe 2 O 3 @CoFe 2 O 4 , rGO/α-Fe 2 O 3 , B­(OH) 3 /α-Fe 2 O 3 –CMSs, Fe 3 O 4 @C, Fe 3 O 4 @SiO 2 , Fe 3 O 4 @SnO 2 , and RGO/Fe 3 O 4 /ZnO et al In this paper, the one-step reduction hydrothermal method was used to synthesize α-Fe 2 O 3 and Fe 3 O 4 composites, and the excellent EM absorption performance has been reached with the smallest reflection loss (RL) of −43.1 dB near 2.0 mm; the effective bandwidth of absorbing is 3.4 GHz (9.8–13.2 GHz).…”