Hydrogen isotope separation with nanoporous materials is a very challenging yet promising approach. To overcome the limitation of the conventional isotope separation strategy, quantum sieving-based separation using nanoporous materials has been investigated recently. In this study, to see the thermodynamic deuterium separation phenomena attributed to the chemical affinity quantum sieving effect, we examine Hofmann-type metal–organic frameworks (MOFs), Co(pyz)[M(CN)₄] (pyz = pyrazine, M = Pd²⁺, Pt²⁺, and Ni²⁺), which have microporosity (4.0 × 3.9 Ų) and an extraordinarily high density of open metal sites (∼9 mmol/cm³). Owing to the preferential adsorption of D₂ over H₂ at strongly binding open metal sites, the Hofmann-type MOF, Co(pyz)[Pd(CN)₄] exhibited a high selectivity (S_D2/H2) of 21.7 as well as a large D₂ uptake of 10 mmol/g at 25 K. This is the first study of Hofmann-type MOFs to report high selectivity and capacity, both of which are important parameters for the practical application of porous materials toward isotope separation.

中文翻译：

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使用具有高密度开放金属位点的 Hofmann 型金属-有机框架热力学分离氢同位素

用纳米多孔材料分离氢同位素是一种非常具有挑战性但很有前景的方法。为了克服传统同位素分离策略的局限性，最近研究了使用纳米多孔材料的基于量子筛分的分离。在这项研究中，为了了解归因于化学亲和量子筛分效应的热力学氘分离现象，我们研究了霍夫曼型金属有机骨架 (MOF)、Co(pyz)[M(CN) ₄ ] (pyz = 吡嗪，M = Pd ²⁺、Pt ²⁺和 Ni ²⁺），它们具有微孔（4.0 × 3.9 Å ²）和极高密度的开放金属位点（~9 mmol/cm ³）。由于 D _{2的优先吸附}在 H ₂的强结合开放金属位点上，霍夫曼型 MOF, Co(pyz)[Pd(CN) ₄ ] 表现出 21.7 的高选择性 ( S _{D 2 /H 2} ) 以及大的 D ₂吸收在 25 K 时为 10 mmol/g。这是 Hofmann 型 MOF 的首次研究，报告了高选择性和容量，这两者都是多孔材料实际应用于同位素分离的重要参数。