Xu Zhi-Xun, Wang Yi-Ming, Lin Li-Chiang
Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Avenue, Columbus, Ohio 43210, United States.
ACS Appl Mater Interfaces. 2023 Oct 11;15(40):47081-47093. doi: 10.1021/acsami.3c10710. Epub 2023 Sep 27.
Metal-organic frameworks (MOFs) have recently drawn considerable attention as promising adsorbents to harvest atmospheric water. To achieve an efficient harvesting process, seeking MOFs that demonstrate sharp condensation behavior is the key. Given that the clustering of water molecules in MOFs should be driven by not only MOF-water interactions but also water-water interactions, the spatial arrangement of water adsorption sites in a MOF is therefore crucial. Specifically, this study demonstrates the critical role of continuous adsorption channels (CACs) in MOFs. Such CACs will enable water molecules to stay in proximity and in a continuous manner, thus promoting the formation of hydrogen bonds and, consequently, the clustering of water molecules. We have developed an automatic algorithm to detect CACs based on the energy grid of host-guest interactions and applied the algorithm to more than 2000 diverse structures. The results show that more than 80% of the studied MOFs displaying water condensation at 298 K and 20% relative humidity predicted by Monte Carlo simulations indeed have CACs. The developments herein are anticipated to largely facilitate the future discovery of optimal adsorbents for water harvesting or water-adsorption-related applications in general. A Python-based code for detecting CACs in porous materials is also provided along with this article to employ this approach.
金属有机框架材料（MOFs）作为一种有望用于收集大气水的吸附剂，近来备受关注。要实现高效的收集过程，关键在于寻找具有明显冷凝行为的MOFs。鉴于MOFs中水分子的聚集不仅受MOF - 水相互作用驱动，还受水 - 水相互作用驱动，因此MOF中水吸附位点的空间排列至关重要。具体而言，本研究证明了MOFs中连续吸附通道（CACs）的关键作用。这种CACs能使水分子以连续的方式保持在附近，从而促进氢键的形成，进而促使水分子聚集。我们开发了一种基于主客体相互作用能量网格检测CACs的自动算法，并将该算法应用于2000多种不同结构。结果表明，蒙特卡罗模拟预测在298 K和20%相对湿度下显示水冷凝的MOFs中，超过80%确实具有CACs。本文的进展有望极大地促进未来用于水收集或一般与水吸附相关应用的最佳吸附剂的发现。本文还提供了一个基于Python的用于检测多孔材料中CACs的代码，以采用这种方法。
