Thermal conversion of wheat-like metal organic frameworks to achieve MgO/carbon composites with tunable morphology and microwave response
Thermal conversion of wheat-like metal organic frameworks to achieve MgO/carbon composites with tunable morphology and microwave response
复制标题
类小麦金属有机骨架的热转化以获得具有可调节形貌和微波响应的MgO/碳复合材料
DOI：
10.1039/c8tc03628d
复制
发表时间：
2018
影响因子：
6.4
通讯作者：
Ji Guangbin
中科院分区：
文献类型：
--
作者：
Quan Bin;Liang Xiaohui;Yi Heng;Chen Yutian;Xiang Junxian;Xu Guoyue;Ji Guangbin
介质材料具有良好的化学稳定性、低密度和良好的微波耗散性能，是吸波材料的重要组成部分。如何提高其复介电常数一直是研究的热点。介电常数与极化和电导密切相关。提高极化行为和电导率的途径有很多，因此采用混合方法来实现多种损耗机制的集成是非常常见的。然而，也不可避免地存在粒子分布不均匀、界面粗糙、重复性差等问题。在这里，我们报告了一种简单的热转换策略，使氧化镁能够嵌入石墨化的碳基质中。随着加热条件的变化，可以得到形貌不同、导电性不同的纳米多孔碳织构，这有利于增强极化过程和电导衰减。因此，所得到的纳米复合材料可以实现可控的性能，如有效带宽的扩展，最大吸收峰向低频移动，以及轻量化的特性。这些发现为金属有机骨架(MOF)的应用潜力提供了新的见解；此外，我们的方法为合理设计完成众多优化策略提供了一个很好的案例研究。
Dielectric materials are essential parts of microwave absorbers due to their good chemical stability, low density and excellent microwave dissipation. How to enhance their complex permittivity has been a research focus. The dielectric constant is closely related to polarization and conduction. There are many pathways to boost polarization behaviors and electrical conductivity, so hybrid methods are very common to realize integration of multiple loss mechanisms. However, there are inevitable issues such as heterogeneous distribution of particles, rugged interfaces, and poor repeatability. Here, we report a simple thermal conversion strategy to enable magnesium oxide to be embedded in a graphitized carbon matrix. With variation of heating conditions, a nanoporous carbon texture with different morphologies and distinct conductivity can be obtained, which is beneficial to enhanced polarization processes as well as conduction attenuation. Thus, the obtained nanocomposites can achieve controllable performances, such as extension of effective bandwidth, a shift of maximum absorbing peaks towards low frequencies, and lightweight characteristics. These findings provide new insights into the application potential of metal organic frameworks (MOFs); in addition, our method offers a good case study of a rational design to complete numerous optimization strategies.