MOFs复合衍生法制备Co/Ni/C@CNTs及吸波性能增强研究

Synthesis of Co/Ni/C@CNTs by a MOFs-based composites-derivedtechnique with improved microwave absorption performance

采用液相研磨法制取ZIF-67/Ni^(2+)/三聚氰胺复合前驱体,经由高温热解衍生制得Co/Ni/C@CNTs复合物。结果表明,复合物主体为微米级片状多孔碳框架,框架内均匀分布Co、Ni纳米粒子,框架表面存在短碳纳米管。片状石墨化碳框架以及CNTs的存在有利于低填充度下导电网络的构建和导电损耗的增强,Co/C、Ni/C界面结构、碳材料的缺陷等也有助于极化损耗的增强,磁性Co、Ni纳米粒子也提供了磁损耗,改善了阻抗匹配。因此,最佳样品在20%(质量分数)的填充度,1.7 mm厚度下的有效吸收频带宽达5.6 GHz。本研究不仅丰富了MOFs衍生物的结构设计与调控研究,也为碳基吸波材料的轻质宽频研究提供了新思路。

ZIF-67 composites are prepared by grinding ZIF-67,melamine with Ni^(2+)solution,which are then successfully transformed into Co/Ni/C@CNTs composites after controllable high-temperature annealing.As-obtained composites are mainly composed of micron-sized flaky porous carbon frameworks.And Co,Ni nanoparticles are uniformly distributed in the porous carbon,and short CNTs are also observed on the surface of porous carbon.The results show that flaky carbon and CNTs possess positive effect on the construction of conductive networks and enhancement of conduction loss,when low filling ratio of MAMs is chosen.Co/C,Ni/C interface structure and defects in carbon are conducive to the improvement of polarization loss.And magnetic Co,Ni nanoparticles benefit both magnetic loss and impedance matching.Therefore,the effective absorption bandwidth of optimal sample can reach 5.6 GHz,when the filling ratio and matching thickness are only 20 wt%and 1.7 mm,respectively.This research may not only promote the research on the structure design and control of MOF-derived materials,but also shed new light on the development of carbon-based lightweight MAMs with wide absorption frequency range.