Modulated Hydrothermal Synthesis of UiO-66(Hf)-Type Metal-Organic Frameworks for Optimal Carbon Dioxide Separation
Modulated Hydrothermal Synthesis of UiO-66(Hf)-Type Metal-Organic Frameworks for Optimal Carbon Dioxide Separation
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DOI：
10.1021/acs.inorgchem.5b02312
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发表时间：
2016-02-01
影响因子：
4.6
通讯作者：
Zhao, Dan
中科院分区：
文献类型：
--
作者：
Hu, Zhigang;Nalaparaju, Anjaiah;Zhao, Dan
近年来，人们对铪（Hf）金属有机框架（MOFs）的兴趣越来越大。由于存在对吸附物具有高亲和力的布朗斯台德酸位点，以及与其Zr类似物类似的突出的化学和水热稳定性，这些M0 F可以比锆（Zr）M0 F更好地作为气体吸附剂。然而，由于缺乏有效的合成方法，Hf-MOFs的报道很少。本文报道了UiO-66（Hf）型MOFs的调制水热合成。在这些MOFs中，UiO-66（Hf）-（OH）（2）在0.15 bar和298 K下具有1.81 mmol g（-1）的非常高的CO2重量吸收，这比UiO-66（Hf）（0.36 mmol g（-1））高400%。它还表现出在1 bar和298 K下167 v/v的创纪录的CO2体积吸收率。理想吸附溶液理论计算表明，CO2/N-2（摩尔比15：85）的选择性为93和CO2/H-2（摩尔比30：70）的选择性高于1700。突破性的模拟也证实了其最佳的二氧化碳分离属性。我们的研究结果首次证明了Hf-MOFs作为先进吸附剂用于高性能CO2相关分离的强大潜力。
Recently, there has been growing interest in hafnium (Hf) metal-organic frameworks (MOFs). These MOFs may perform better as gas adsorbents than zirconium (Zr) MOFs due to the presence of Bronsted acid sites with high affinity toward adsorbates, together with the outstanding chemical and hydrothermal stabilities similar to their Zr analogues. However, Hf-MOFs have been rarely reported due to the lack of effective synthetic methods. We herein report a modulated hydrothermal synthesis of UiO-66(Hf)-type MOFs. Among these MOFs, UiO-66(Hf)-(OH)(2) possesses a very high CO2 gravimetric uptake of 1.81 mmol g(-1) at 0.15 bar and 298 K, which is 400% higher than that of UiO-66(Hf) (0.36 mmol g(-1)). It also exhibits a record-high volumetric CO2 uptake of 167 v/v at 1 bar and 298 K. Ideal adsorbed solution theory calculations showed a CO2/N-2 (molar ratio 15:85) selectivity of 93 and CO2/H-2 (molar ratio 30:70) selectivity above 1700. Breakthrough simulations also confirmed its optimal CO2 separation attribute. Our results have demonstrated for the first time the strong potential of Hf-MOFs for advanced adsorbents for high-performance CO2-related separations.