Department of Physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Iran.
Phys Chem Chem Phys. 2023 May 10;25(18):13145-13154. doi: 10.1039/d3cp00897e.
Recently, with the increasing progress of telecommunication systems and the development of high-range antennas, especially microwave antennas, the pollution caused by them has become very worrying. So, many efforts are being made to design absorbents which protect the environment from electromagnetic waves. Many reports have proved the extraordinary effect of absorbents containing carbon and ferrites. Here, the microwave absorption capabilities of two samples of CuFeO/MWCNT composites (annealed at 400 °C and unannealed) were studied in which CuFeO nanoparticles (NPs) were decorated on multiwalled carbon nanotubes (MWCNTs) a two-step method. First, CuFeO NPs were synthesized at an optimum condition to have narrow size distribution (<10 nm) and high saturation magnetization of 47 emu g. Then, the CuFeO NPs were used to decorate MWCNTs affording CuFeO/MWCNT. Half of CuFeO/MWCNT was annealed at 400 °C for 3 h and the rest of CuFeO/MWCNT remained nonannealed. The minimum reflection loss (RL) in the nonannealed sample was -46.4 dB at 16 GHz for a 2.8 mm thickness. While, for the annealed sample, RL reached -69 dB at 10 GHz for a 3.4 mm thickness. In the nonannealed sample, the effective absorption bandwidth was 3.8 GHz, but this value was significantly increased to 8.5 GHz for the annealed sample at 3.2 and 3.4 mm thickness, which covered whole X and Ku bands.
最近，随着电信系统的不断进步和高增益天线的发展，特别是微波天线，它们所造成的污染变得非常令人担忧。因此，人们正在努力设计能够保护环境免受电磁波污染的吸收剂。许多报告已经证明了含有碳和铁氧体的吸收剂的非凡效果。在这里，研究了两种 CuFeO/MWCNT 复合材料（在 400°C 下退火和未退火）的微波吸收能力，其中 CuFeO 纳米颗粒（NPs）通过两步法装饰在多壁碳纳米管（MWCNTs）上。首先，在最佳条件下合成 CuFeO NPs，以具有窄的尺寸分布（<10nm）和 47 emu g 的高饱和磁化强度。然后，将 CuFeO NPs 用于装饰 MWCNTs，得到 CuFeO/MWCNT。CuFeO/MWCNT 的一半在 400°C 下退火 3 小时，其余部分保持未退火。未退火样品在 2.8mm 厚度下的最小反射损耗（RL）为-46.4dB，在 16GHz 时。然而，对于退火样品，在 3.4mm 厚度下 RL 达到-69dB，在 10GHz 时。在未退火样品中，有效吸收带宽为 3.8GHz，但对于退火样品，该值显著增加到 8.5GHz，在 3.2 和 3.4mm 厚度下，覆盖整个 X 和 Ku 波段。
