Dendritic α-Fe2O3 nanostructures: facile hydrothermal synthesis, characterization and microwave absorption

Synthesis, structure, magnetism and photocatalysis of α-Fe2O3nanosnowflakes

“…The remanent magnetizations (M r ) at 300 K were determined to be 0.26 and 0.22 emu g À1 for the snowake-like and dendrite-like structures, respectively, from the magnetization curves. All these values are comparable to those of other works, 14,[37][38][39][40][41][42] as seen in Table 1. However, the two samples show much higher coercivities (H c , 2997 Oe for the snowake structure and 2749 Oe for the dendrite-like structure) compared to those reported by others (no higher than 1610 Oe, see Table 1).…”

Morphology-Controlled Fabrication Strategy of Hollow Mesoporous Carbon Spheres@f-Fe2O3 for Microwave Absorption and Infrared Stealth

“…The FT-IR spectra of HMCS@f-Fe 2 O 3 - x are presented in Figure b. The broad peak centered at 3424 cm –1 was associated with the stretching vibration of −OH caused by absorbed water, while the peak that appeared at 1622 cm –1 was ascribed to the stretching vibration of the aromatic CC present in the carbon layer . Besides, the absorption peaks at 473 and 557 cm –1 were assigned to the Fe–O stretching vibration, confirming the existence of α-Fe 2 O 3 phase. , Typically, for α-Fe 2 O 3 , the peak at ∼1068 cm –1 was associated with the formation of hematite.…”

“…α-Fe 2 O 3 is a high-temperature-resistant N-type semiconductor component with considerable dielectric loss capability and frequency-insensitive dielectric parameters (ε′ and ε″), which contribute to the impedance matching at high frequencies. , Furthermore, different shapes (dendritic-like, rod-like, burr-like, etc.) have been fabricated to enhance the dissipation effect of EMW, among which the flake structure with large heterogeneous surfaces can generate rich polarization effects and increase the interface scattering, thereby regulating the absorption performance. − Besides, since flake particles have larger contact areas than other shapes, the real part of their complex permittivity ε′ remains comparatively higher with the increase of temperature, resulting in reduced infrared emissivity, with ranges of <0.6 (3–5 μm) and <0.83 (8–14 μm) below 800 °C . Significantly, the dielectric parameters can be optimized by fine-tuning the elaborate morphology to enhance MA performance and reduce infrared emission characteristics, while it is quite difficult to control the dispersion and orientation of flake particles with high surface energy in the composites.…”