本文要点：
本征孔隙率和流动性的特点赋予了多孔液体 （PLs） 独特的性能和性能，但由于难以液化并同时保持多孔特性，PLs 的制备仍然具有挑战性。
在此，作者开发了一种逐步表面功能化和离子交换策略，以实现基于柔性共价有机框架 （COF） 的多孔液体 （COF-PLs） 的罕见例子。
通过在明智选择的三维柔性 COF-301 的外表面涂覆咪唑盐电晕，然后使用阴离子冠层聚乙二醇）磺酸盐钾 （PEGS） 通过静电相互作用液化，获得柔性多孔液体 COF-301-PL。
理论计算和 CO2 吸附实验表明，COF-301-PL 的空腔会随着 CO2 压力的变化而发生动态调整。动态膨胀效应不仅可以提供额外的气体吸附能力（40 bar 时为 7.04 mmol/g），还可以促进催化过程中气体分子的质量传递。
因此，COF-301-PL 在将 CO2 转化为环状碳酸盐方面表现出优异的催化效率，与 PEGS 和 COF-301 固体对应物相比，分别提高了 24 倍和 17 倍。
底物吸附和传质条件的优化提高了催化反应的整体效率。这项工作为 PLs 的制备及其在气体吸附和催化中的巨大潜在应用提供了新的视角。
Scheme 1. Schematic of the synthesis of the stable porous COF liquid COF-301-PL through the strategy of constructing corona-canopy electrostatic interaction interfaces.
Figure 1. (a) The PXRD pattern and Rietveld refinement of COF-301 framework. (b) Schematic illustration of the flexible dia-topology network and the 7-fold interpenetrated structure of COF-301. (c) FT-IR spectra of COF-301, COF-301-Im and COF-301-PL. Soild-state13C CP-MAS spectra of COF-301 (d) and COF-301-Im (e). (f) High-resolution N 1s XPS spectra of COF-301 and COF-301-Im. (g) N2 sorption isotherms of the COF301 and (h) COF-301-Im. i The TGA curves of PEGS, COF-301-Im and COF-301-PL.
Figure 2. (a) The high-pressure CO2 adsorption isotherms of pure PEGS and COF-301-PL at 298 K (0-43 bar). (b) The positron lifetime traces of COF-301-PL collected at 298 K. (c) The DSC curves of pure PEGS and COF301-PL. (d) Oscillation-dependent modulus plots of COF-301-PL (filled circles for storage modulus G' and open circles for loss modulus G'').
Figure 3. MD snapshots displaying COF-301
Figure 4. (a) The experimental results of CO2 catalytic conversion with different adsorbents. The CO2 catalytic conversion of PEGS (b) and COF-301-PL (c) under different gas pressures. (d) The average CO2 catalytic conversion increment per 1 bar pressure for PEGS and COF-301-PL under different pressure conditions.
Figure 5. (a) PXRD patterns of the COF-301-np phase, along with its Rietveld refinement results and unit cell parameters. (b) The crystal cell structures of COF-301-np and COF-301-lp phases with the geometric configurations of molecular fragments within the framework. (c) PXRD patterns of the COF-301-lp phase, along with its Rietveld refinement results and unit cell parameters. (d) The comparative PXRD patterns of COF301-npand COF-301-lp phases. (e) The precise structures of the dia topology network in both COF-301-np and COF-301-lp phases obtained through Rietveld refinement. (f) High-pressure CO2 adsorption isotherms of COF301 and COF-301-PL (without PEGS) compared with simulated CO2 adsorption curves of COF-301-np and COF-301-lp phases.
https://doi.org/10.1093/nsr/nwaf032
