Diamine-functionalized metal-organic framework: exceptionally high CO2 capacities from ambient air and flue gas, ultrafast CO2 uptake rate, and adsorption mechanism
Diamine-functionalized metal-organic framework: exceptionally high CO2 capacities from ambient air and flue gas, ultrafast CO2 uptake rate, and adsorption mechanism
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DOI：
10.1039/c3ee42328j
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发表时间：
2014-02-01
影响因子：
32.5
通讯作者：
Hong, Chang Seop
中科院分区：
文献类型：
--
作者：
Lee, Woo Ram;Hwang, Sang Yeon;Hong, Chang Seop
通过后改性法制备了以伯胺为主体的en- mg -2(dobpdc) （1-en; en =乙二胺）骨架。从同步加速器PXRD数据中可以看出，在接枝吸收en和CO2后，电池参数发生了变化。在25℃和1 bar时，1-en吸附的CO2量为4.57 mmol g(-1) (16.7 wt%)，在150℃时减少到3.00 mmol g(-1) （11.7 wt%）。值得注意的是，1-en在0.15 bar时显示出显著的CO2吸收量（3.62 mmol g(-1), 13.7 wt%），这与燃烧后烟气的CO2分压相当。在0.39 mbar下，1-en的CO2容量为2.83 mmol g(-1) (11.1 wt%)，接近大气CO2浓度，是mof中最高的。1-en在CO2捕集过程中的等容吸附热（-Q(st)）为49 ~ 51 kJ mol(-1)， DFT计算结果为-52.8 kJ mol（-1）。这些结果表明CO2吸附到en的游离胺上导致氨基甲酸的形成。在空气和烟气的实际稀释浓度下建立的二氧化碳吸附-解吸循环几乎保留了二氧化碳的容量，这可能为二氧化碳捕获的实际应用提供了巨大的潜力。1-en对CO2的吸附速率超过了其他一些被测多孔材料。即使在暴露于湿度后，1-en的二氧化碳吸收可回收性仍保持不变。
A framework en-Mg-2(dobpdc) (1-en; en = ethylenediamine) functionalized with the primary amine en was prepared via postmodification. From synchrotron PXRD data, it is revealed that the cell parameters change upon grafting of en and CO2 uptake. The adsorbed CO2 amount of 1-en is 4.57 mmol g(-1) (16.7 wt%) at 25 degrees C and 1 bar and decreases to 3.00 mmol g(-1) (11.7 wt%) at 150 degrees C. Noticeably, 1-en shows a significant CO2 uptake (3.62 mmol g(-1), 13.7 wt%) at 0.15 bar, which is comparable to the CO2 partial pressure of a post-combustion flue gas. The CO2 capacity of 1-en at 0.39 mbar, close to atmospheric CO2 concentration, is 2.83 mmol g(-1) (11.1 wt%), which marks the highest amount among MOFs. The isosteric heat of adsorption (-Q(st)) of 1-en in CO2 capture corresponds to 49-51 kJ mol(-1), which is supported by DFT calculations (-52.8 kJ mol(-1)). These results suggest that the adsorption of CO2 onto the free amines of en leads to the formation of a carbamic acid. Adsorption-desorption cyclings of CO2 at the real dilute concentrations of air and flue gas are established with almost retaining CO2 capacities, which could provide superior potential for practical application in CO2 capture. The adsorption rate of CO2 in 1-en exceeds that in some other tested porous materials. The recyclability in CO2 uptake for 1-en is maintained even after exposure to humidity.