Low-Cost
Carbothermal Reduction Preparation of Monodisperse Fe<sub>3</sub>O<sub>4</sub>/C Core–Shell Nanosheets for Improved Microwave Absorption
Yun Liu
Yiwei Fu
Lin Liu
Wei Li
Jianguo Guan
Guoxiu Tong
10.1021/acsami.8b02770.s001
https://acs.figshare.com/articles/journal_contribution/Low-Cost_Carbothermal_Reduction_Preparation_of_Monodisperse_Fe_sub_3_sub_O_sub_4_sub_C_Core_Shell_Nanosheets_for_Improved_Microwave_Absorption/6205133
This
paper demonstrates a facile and low-cost carbothermal reduction preparation
of monodisperse Fe<sub>3</sub>O<sub>4</sub>/C core–shell nanosheets
(NSs) for greatly improved microwave absorption. In this protocol,
the redox reaction between sheet-like hematite (α-Fe<sub>2</sub>O<sub>3</sub>) precursors and acetone under inert atmosphere and
elevated temperature generates Fe<sub>3</sub>O<sub>4</sub>/C core–shell
NSs with the morphology inheriting from α-Fe<sub>2</sub>O<sub>3</sub>. Thus, Fe<sub>3</sub>O<sub>4</sub>/C core–shell NSs
of different sizes (<i>a</i>) and Fe<sub>3</sub>O<sub>4</sub>/C core–shell nanopolyhedrons are obtained by using different
precursors. Benefited from the high crystallinity of the Fe<sub>3</sub>O<sub>4</sub> core and the thin carbon layer, the resultant NSs exhibit
high specific saturation magnetization larger than 82.51 emu·g<sup>–1</sup>. Simultaneously, the coercivity enhances with the
increase of <i>a</i>, suggesting a strong shape anisotropy
effect. Furthermore, because of the anisotropy structure and the complementary
behavior between Fe<sub>3</sub>O<sub>4</sub> and C, the as-obtained
Fe<sub>3</sub>O<sub>4</sub>/C core–shell NSs exhibit strong
natural magnetic resonance at a high frequency, enhanced interfacial
polarization, and improved impedance matching, ensuring the enhancement
of the microwave absorption. The 250 nm NSs–paraffin composites
exhibit reflection loss (RL) lower than −20 dB (corresponding
to 99% absorption) in a large frequency (<i>f</i>) range
of 2.08–16.40 GHz with a minimum RL of −43.95 dB at <i>f</i> = 3.92 GHz when the thickness is tuned from 7.0 to 1.4
mm, indicating that the Fe<sub>3</sub>O<sub>4</sub>/C core–shell
NSs are a good candidate to manufacture high-performance microwave
absorbers. Moreover, the as-developed carbothermal reduction method
could be applied for the fabrication of other composites based on
ferrites and carbon.
2018-04-19 00:00:00
shape anisotropy effect
as-developed carbothermal reduction method
carbothermal reduction preparation
RL
α- Fe 2 O 3
Low-Cost Carbothermal Reduction Preparation
microwave absorption
Fe 3 O 4 core
NS
Fe 3 O 4