Fabrication of Hollow Cube Dual-Semiconductor Ln<sub>2</sub>O<sub>3</sub>/MnO/C Nanocomposites with Excellent Microwave Absorption Performance
Zhongjing Shen, Chongbo Liu, Huili Yang, Yu Xie, Qingwen Zeng, Renchao Che
Abstract
Metal–organic frameworks (MOFs) have been verified as ideal precursors for preparing highly effective microwave absorbers. However, it is still challenging to fabricate a thin, lightweight, and well-organized nanostructure with strong microwave absorption (MA) capability and wide absorption bandwidth. In this study, hollow cube dual-semiconductor Ln2O3/MnO/C (Ln = Nd, Gd, Er) nanocomposites, which are effective microwave absorbers, have been fabricated via one-step high-temperature carbonization of Ln-Mn-MOFs. The effect of band gap on the MA performance of various nanocomposites synthesized at the same carbonization temperature is investigated. Gd2O3/MnO/C-800 shows superior MA capacity with maximum reflection loss (RLmax) of −64.4 dB at 12.8 GHz and 1.86 mm-thickness. When the thickness is 1.44 mm, the RL value is obtained as −52.7 dB at 16.8 GHz, and at a low frequency of 4.36 GHz and thickness of 4.59 mm, the RL value reaches −56.4 dB. Further, the effect of temperature on the MA properties of Gd2O3/MnO/C is examined. The results reveal that Gd2O3/MnO/C-700 has an ultrahigh MA bandwidth of 6.6 GHz, covering the entire Ku bands at 2.09 mm-thickness. Overall, this work demonstrates a facile strategy to construct hollow, homogeneous ternary composites with outstanding MA performance.