Ashraf Shumaila, Liu Caixia, Li Shuai, Haq Ihtisham-Ul, Mehmood Mehwish, Li Pengfei, Wang Bo
Key Laboratory of Cluster Science Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic, Advanced Research Institute of Multidisciplinary Science, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
School of Mathematics and Statistics, University of Lahore, Lahore, Pakistan.
ACS Appl Mater Interfaces. 2020 Sep 9;12(36):40372-40380. doi: 10.1021/acsami.0c12317. Epub 2020 Aug 25.
Anionic covalent organic framework is an emerging class of functional materials in which included ionic species of the opposite charges play an important role in the ion conduction and selective gas adsorption. Herein, we reported a facile method to construct a series of germanate-based anionic COFs (Ge-COFs) by reticulating dianionic hexa-coordinated GeO nodes with anthracene building blocks adopting a topology in an extended 2D framework. A systematic change of pore properties in Ge-COFs was observed through the incorporation of three different alkali metal cations: Li, Na, and K. The intrinsically negatively charged backbone provides a host matrix with a homogeneous distribution of counter cations and poses variable and exciting features for gas adsorption and ionic conduction. Among the series, K-based Ge-COF-K with a surface area of 1252 m/g and pore volume of 0.84 cm/g shows a maximum CO uptake of 126 cm/g (247.4 mg/g) at 273 K and 1 bar, an IAST selectivity of 140 over N. Ge-COF-K also exhibits a high SO kinetic breakthrough capacity of 154 mg/g at low ppm of SO concentration under ambient conditions among recently reported porous materials. Moreover, reasonably high lithium, sodium, and potassium ionic conductivities were observed with the values of 1.2 × 10, 3.4 × 10, and 2.2 × 10 S/cm for propylene carbonate infiltrated Ge-COF-Li, Ge-COF-Na, and Ge-COF-K at 100 °C, respectively.
阴离子共价有机框架是一类新兴的功能材料，其中包含的带相反电荷的离子物种在离子传导和选择性气体吸附中起着重要作用。在此，我们报道了一种简便的方法，通过在扩展的二维框架中采用拓扑结构，用蒽构建块将二价阴离子六配位GeO节点网状化，构建一系列基于锗酸盐的阴离子COF（Ge-COF）。通过引入三种不同的碱金属阳离子Li、Na和K，观察到Ge-COF中孔性质的系统变化。本质上带负电荷的主链提供了一个主体基质，其中抗衡阳离子均匀分布，并为气体吸附和离子传导带来了可变且令人兴奋的特性。在该系列中，表面积为1252 m²/g、孔体积为0.84 cm³/g的基于K的Ge-COF-K在273 K和1 bar下显示出最大CO吸附量为126 cm³/g（247.4 mg/g），相对于N₂的IAST选择性为140。在最近报道的多孔材料中，Ge-COF-K在环境条件下低ppm SO₂浓度下还表现出154 mg/g的高SO₂动力学突破容量。此外，对于在100°C下碳酸丙烯酯渗透的Ge-COF-Li、Ge-COF-Na和Ge-COF-K，分别观察到相当高的锂、钠和钾离子电导率，其值分别为1.2×10⁻⁴、3.4×10⁻⁴和2.2×10⁻⁴ S/cm。
