Orbital Trap of Xenon: Driving Force Distinguishing between Xe and Kr Found at a Single Ag(I) Site in MFI Zeolite at Room Temperature
Orbital Trap of Xenon: Driving Force Distinguishing between Xe and Kr Found at a Single Ag(I) Site in MFI Zeolite at Room Temperature
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DOI：
10.1021/acs.jpcc.2c01515
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发表时间：
2022-05-19
影响因子：
3.7
通讯作者：
Kuroda, Yasushige
中科院分区：
文献类型：
--
作者：
Oda, Akira;Kouzai, Hiroe;Kuroda, Yasushige
稀有气体（Ng）元素由于其八重电子构型而稳定，因此Ng的捕获和纯化具有高度挑战性。在这里，我们展示了一个新的概念，这些应用：轨道陷阱的电子。这一概念是在室温（RT）下在MFI沸石中Ag（I）的单中心吸附/分离过程中发现的。实验和计算表明，沸石晶格配位的Ag（I）单离子具有良好的电子接受性质，从而诱导了Ag（I）5p-> Ag（I）5s施主轨道相互作用，即使在低压区和室温下也能与Ag（I）形成稳定的σ键。由于Kr 4p-> Ag（I）5s供体轨道相互作用的不稳定性，在室温下Kr吸附的稳定σ键没有建立，这反映了Kr 4p轨道的相对高能量。因此，单一Ag（I）位点使其能够在室温下区分H2O和Kr;使用含有高浓度单一Ag（I）位点的Ag/MFI在室温下实现了H2O/Kr气体混合物的H2O分离。我们的研究结果表明，利用多孔材料的局部结构的轨道捕集器显示出作为选择性地收集有害气体（空气浓度仅为0.087 ppm）的有效方法的前景。它有助于扩大成本昂贵的光纤的应用范围。
Noble gas (Ng) elements are stable because of their octet electronicconfiguration, and thus Ng capture and purification are highly challenging. Here, weshow a new concept for these applications: an orbital trap for Xe. This concept wasfound in Xe adsorption/separation processes at room temperature (RT) at the singleAg(I) site in MFI zeolite. Experiments and calculations showed the zeolite lattice-coordinated Ag(I) single ion has excellent electron-accepting nature and therebyinduces the Xe 5p -> Ag(I) 5s donation orbital interaction, forming a stable Sigma-bondwith Xe even in the lower-pressure region and at RT. By contrast, the stable Sigma-bond forKr adsorption is not established at RT because of the instability of the orbitalinteractions of the Kr 4p -> Ag(I) 5s donation, as reflected from the relatively high energy of the Kr 4p orbital. Thus, the singleAg(I) site allows it to distinguish between Xe and Kr at RT; the Xe separation from the Xe/Kr gas mixture was achieved at RT usingthe Ag/MFI containing a high concentration of single Ag(I) sites. Ourfindings suggest that the orbital Xe trap using the localstructure of porous materials shows promise as an efficient approach to selectively collect Xe (air concentration 0.087 ppm only). Itwill help to expand the range of applications of the costly Xe.