二维金属有机框架材料的制备及其应用

二维金属有机框架（MOFs）作为一类新型的二维多孔材料,具有厚度小、比表面积大、孔隙率高、可接触活性位点丰富等优点,在众多领域都具有研究和潜在的应用价值。本文简要综述了近年来二维MOFs的制备方法,包括“自上而下”和“自下而上”两种策略。自上而下法操作简单,有广泛的适用性;自下而上法可以通过控制实验条件在一定程度上实现对材料的可控制备。阐述了二维MOFs在电化学储能、催化、传感、气体分离等领域的应用研究。深层剖析了二维MOFs的特性对储能器件电化学性能以及反应催化活性的影响。此外,二维MOFs的高电导率和电荷转移率还促进了其在电化学传感器方面的发展;基于二维MOFs的分子筛膜也越来越受到研究人员的关注。最后指出了二维MOFs存在易团聚、厚度难以精确控制、制取成本较高、产率偏低等问题,提出了解决方案及其未来的发展方向。     

Modified nano-CaCO3 hard template method for hierarchical porous carbon powder with enhanced electrochemical performance in lithium-sulfur battery

Lithium-sulfur (Li-S) battery was the most promising energy storage devices with ultrahigh energy density (2600 Wh kg⁻¹). But it was impeded by poor electronic conductivity, serious shuttle effect, and enormous volume expansion. Herein, hierarchical porous carbons were simply prepared by a modified nano-CaCO₃ hard-template method from glucose. The template-removal step was modified from HCl washing to HCl soaking. This allowed the microstructure of carbon product significantly involved. Furthermore, the mass ratio of CaCO₃ nanoparticles and glucose played an important role in booming of hierarchical porous and specific surface area. When integrated with S, functioned as cathode in Li-S battery, improved electrochemical performances were exhibited, such as high initial discharge capacity and good capacity retention. This modified hard-template method suggested a promising way to fabricate hierarchical porous carbon matrix available to apply in advanced Li-S battery.