Prolonged HKUST-1 functionality under extreme hydrothermal conditions by electrospinning polystyrene fibers as a new coating method
Prolonged HKUST-1 functionality under extreme hydrothermal conditions by electrospinning polystyrene fibers as a new coating method
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DOI：
10.1016/j.micromeso.2018.05.004
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发表时间：
2018-11-01
影响因子：
5.2
通讯作者：
Mu, Bin
中科院分区：
文献类型：
--
作者：
Armstrong, Mitchell;Sirous, Peyman;Mu, Bin
金属-有机骨架（MOF） HKUST-1 （CuBTC）因其开放的金属位点、简单的合成方法和较低的合成成本而被认为是一种很有前途的吸附剂。然而，与实际应用相关的一大挑战是其水稳定性差。合成的hkust - 1粉体的孔隙率在不到一个月的时间内可降低50%，在高湿高温的环境下可在数天内分解。在这项工作中，我们证明了在hust -1表面包裹一层薄的疏水聚合物后，水热稳定性大大提高。在静电纺丝过程中，将声化学合成的HKUST-1粉末悬浮在聚苯乙烯涂料溶液中，可将HKUST-1颗粒直接浸渍在聚苯乙烯纤维中。经热重分析证实，HKUST-1的最终载荷为5%。氮等温线没有显示这些纤维中预期的氮吸收；然而，二氧化碳等温线可以。这表明，与SEM图像一致，颗粒被嵌入在聚苯乙烯层下，并且在氮气吸附实验的长度上，氮气无法穿透这层。HKUST-1粉末和5wt %的HKUST-1纤维暴露在极端的水热条件下，以不同的时间步长测量二氧化碳的吸收。纯hust -1粉末在6 h时几乎完全水解降解，但在5 wt%的hust -1浸渍纤维中降解速率减慢，在48 h时仍观察到20%的CO2吸收能力。
The metal-organic framework (MOF) HKUST-1 (CuBTC) has been regarded as a promising adsorbent due to its open metal sites, easy synthesis method, and lower synthesis cost. However, a big challenge related to its practical application is its poor hydrostability. The porosity of as-synthesized HKUST-lpowder may drop 50% in less than one month and it can decompose within days at high humid and hot atmosphere. In this work, we demonstrate that the hydrothermal stability of HKUST-1 is greatly improved after coating it with a thin hydrophobic polymer. The HKUST-1 particles may be directly impregnated in polystyrene fibers during the electrospinning process by suspending sonochemically synthesized HKUST-1 powder in the polystyrene dope solution. It was confirmed that the final HKUST-1 loading was 5% by TGA. Nitrogen isotherms do not show the expected nitrogen uptake in these fibers; however, the carbon dioxide isotherms do. This suggests that the particles are embedded under a layer of polystyrene in agreement with SEM images, and that the nitrogen is unable to penetrate this layer over the length of a nitrogen adsorption experiment. HKUST-1 powder and 5 wt% HKUST-1 fibers are exposed to extreme hydrothermal conditions, and CO2 uptake is measured at varying time steps. Nearly complete hydrolytic degradation of pure HKUST-1 powder is observed at 6 h, but the rate of degradation in the 5 wt% HKUST-1 impregnated fibers is slowed, and 20% CO2 uptake capacity is still observed at 48 h.