Nitrogen-Rich Covalent Triazine Frameworks as High-Performance Platforms for Selective Carbon Capture and Storage
作者:Stephan Hug、Linus Stegbauer、Hyunchul Oh、Michael Hirscher、Bettina V. Lotsch
DOI:10.1021/acs.chemmater.5b03330
日期:2015.12.8
The search for new efficient physisorbents for gas capture and storage is the objective of numerous ongoing researches in the realm of functional framework materials. Here we present the CO2 and H2 uptake capacities of nitrogen rich covalent triazine frameworks (CTFs) based on lutidine, pyrimidine, bipyridine, and phenyl units, showing superior gas uptakes and extremely high CO2 selectivities toward N2. The CO2 uptake of a bipyridine-CTF synthesized at 600 °C (5.58 mmol g–1, 273 K) is the highest reported for all CTFs so far and the second highest for all porous organic polymers (POPs). Moreover, the CO2 selectivity toward N2 of a nitrogen-rich pyrimidine-based CTF synthesized at 500 °C (Henry: 189, IAST: 502) is the highest reported for all POPs, and the H2 uptake of CTF1 synthesized at 600 °C at 1 bar (2.12 wt %, 77 K) is the highest found for all CTFs to date as well. With the wide range of sorption data at hand, we carve out general trends in the gas uptake behavior within the CTF family and nitrogen-containing porous polymers in general, revealing the dominant role of the micropore volume for maximum CO2 uptake, while we find that the nitrogen content is a secondary effect weakly enhancing the CO2 uptake. The latter, however, was identified as the main contributor to the high CO2/N2 selectivities found for the CTFs. Furthermore, ambient water vapor sorption has been tested for CTFs for the first time, confirming the highly hydrophilic nature of CTFs with high nitrogen content.
寻找新的高效气体捕集与封存物理吸附剂是目前功能框架材料领域众多研究的目标。在此,我们介绍了基于鲁替丁、嘧啶、联吡啶和苯基单元的富氮共价三嗪框架(CTFs)对二氧化碳和 H2 的吸收能力,结果表明它们具有优异的气体吸收能力和极高的二氧化碳对 N2 的选择性。在 600 °C 下合成的联吡啶-CTF 的二氧化碳吸收率(5.58 mmol g-1,273 K)是迄今为止所有 CTF 中最高的,也是所有多孔有机聚合物(POP)中第二高的。此外,在 500 °C 下合成的富氮嘧啶基 CTF 对 N2 的 CO2 选择性(Henry:189,IAST:502)是所有 POPs 中最高的,而在 600 °C 1 bar 下合成的 CTF1 对 H2 的吸收率(2.12 wt %,77 K)也是迄今为止所有 CTFs 中最高的。有了这些广泛的吸附数据,我们可以看出 CTF 家族和一般含氮多孔聚合物气体吸收行为的总体趋势,揭示了微孔体积对二氧化碳最大吸收量的主导作用,同时我们发现氮含量只是次要效应,对二氧化碳吸收量的提高作用微弱。然而,后者被认为是 CTF 具有较高 CO2/N2 选择性的主要原因。此外,我们还首次测试了 CTF 的环境水蒸气吸附性,证实了高氮含量 CTF 的高亲水性。