Ahmed Alauddin, Seth Saona, Purewal Justin, Wong-Foy Antek G, Veenstra Mike, Matzger Adam J, Siegel Donald J
Mechanical Engineering Department, University of Michigan, Ann Arbor, MI, 48109, United States.
Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, United States.
Nat Commun. 2019 Apr 5;10(1):1568. doi: 10.1038/s41467-019-09365-w.
Few hydrogen adsorbents balance high usable volumetric and gravimetric capacities. Although metal-organic frameworks (MOFs) have recently demonstrated progress in closing this gap, the large number of MOFs has hindered the identification of optimal materials. Here, a systematic assessment of published databases of real and hypothetical MOFs is presented. Nearly 500,000 compounds were screened computationally, and the most promising were assessed experimentally. Three MOFs with capacities surpassing that of IRMOF-20, the record-holder for balanced hydrogen capacity, are demonstrated: SNU-70, UMCM-9, and PCN-610/NU-100. Analysis of trends reveals the existence of a volumetric ceiling at ∼40 g H L. Surpassing this ceiling is proposed as a new capacity target for hydrogen adsorbents. Counter to earlier studies of total hydrogen uptake in MOFs, usable capacities in the highest-capacity materials are negatively correlated with density and volumetric surface area. Instead, capacity is maximized by increasing gravimetric surface area and porosity. This suggests that property/performance trends for total capacities may not translate to usable capacities.
很少有氢吸附剂能兼顾高的可用体积容量和重量容量。尽管金属有机框架材料(MOF)最近在缩小这一差距方面取得了进展,但大量的MOF阻碍了对最佳材料的识别。在此,我们对已发表的真实和假设的MOF数据库进行了系统评估。通过计算筛选了近500,000种化合物,并对最有前景的化合物进行了实验评估。展示了三种容量超过IRMOF - 20(平衡氢容量的记录保持者)的MOF:SNU - 70、UMCM - 9和PCN - 610/NU - 100。趋势分析表明,在约40 g H/L处存在体积上限。超过这个上限被提议作为氢吸附剂的新容量目标。与早期关于MOF中总氢吸收的研究相反,高容量材料中的可用容量与密度和体积表面积呈负相关。相反,通过增加重量表面积和孔隙率可使容量最大化。这表明总容量的性质/性能趋势可能不适用于可用容量。