A novel method to improve the gas storage capacity of ZIF-8
A novel method to improve the gas storage capacity of ZIF-8
复制标题
提高ZIF-8储气能力的新方法
DOI：
10.1039/c2jm31541f
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发表时间：
2012-01-01
影响因子：
--
通讯作者：
Chen, Guangjin
中科院分区：
文献类型：
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作者：
Mu, Liang;Liu, Bei;Chen, Guangjin
本文提出了一种提高金属有机骨架(MOF)储气量的新方法，即在金属有机骨架中加入适量的水并在其中形成水合物。由于ZIF-8在水气氛中非常稳定，因此采用了商品化的ZIF-8。研究了甲烷在5种不同含水率(0.0%、16.3%、27.7%、30.6%和35.1%，质量分数)的湿ZIF-8分子筛中的吸附和水合物形成行为，并测定了ZIF-8骨架和ZIF-8颗粒床的存储容量。结果表明，湿ZIF-8孔道中会形成水合物，从而显著提高ZIF-8骨架和ZIF-8颗粒床的整体存储容量。水合物对ZIF-8骨架总吸气量的贡献可高达45%。与干态ZIF-8骨架相比，含水率为35.1%的湿态类似物在269.15 K、2.85 Mpa下的净存储容量从5.954 mmolg(-1)提高到9.304 mmolg(-1)，即提高了56%以上。湿法ZIF-8骨架的理想体积存储容量在3.0 Mpa左右时可以达到190V/V以上，比DOE的甲烷存储目标(180V/V)高出7%。此外，我们的扫描电子显微镜测量和X射线衍射分析表明，ZIF-8在饱和过程和水合物形成过程中是稳定的，说明它可以重复使用。
In this work a novel method for enhancing the gas storage capacity of metal-organic frameworks (MOFs), i.e. saturating the MOF with a suitable quantity of water and forming hydrates in it, was proposed. Commercialized ZIF-8 was adopted as it is very stable under an atmosphere of water. The adsorption and hydrate formation behaviors of methane in wet ZIF-8 with five different water contents (0.0%, 16.3%, 27.7%, 30.6%, and 35.1%, mass percentages) were investigated under hydrate formation conditions and the storage capacities of both ZIF-8 frameworks and ZIF-8 particle beds were determined. Our results show that hydrates can form in wet ZIF-8 pores and thus increase the overall storage capacities of both ZIF-8 frameworks and ZIF-8 particle beds remarkably. The contribution of hydrates to the total gas uptake of a ZIF-8 framework can be as high as 45%. Compared with dry ZIF-8 frameworks, the net storage capacity of the wet analogue with a water content of 35.1% increases from 5.954 to 9.304 mmol g(-1) at 269.15 K and 2.85 MPa, in other words, raised by more than 56%. The ideal volume storage capacity of the wet ZIF-8 framework can achieve more than 190 V/V at 3.0 MPa or so, 7% higher than the DOE target (180 V/V) for methane storage. In addition, our SEM measurements and XRD analysis demonstrate that ZIF-8 is stable during the saturation and hydrate formation processes, illustrating that it can be used repeatedly.