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碳材料孔徑分布NLDFT研究最新進展：O2@77K模型

美國麥克儀器 2019-03-04 | 閱讀：2091

近日,，美國麥克儀器公司首席科學家Jeffrey Kenvin博士與資深科學家Jacek Jagiello博士在Journal of Colloid and Interface Science期刊上共同發(fā)表了題為Consistency of carbon nanopore characteristics derived from adsorption of simple gases and 2D-NLDFT Models. Advantages of using adsorption isotherms of oxygen (O₂) at 77K的文章。

在本文的研究中,，作者嘗試采用O₂來進行氣體吸附，因為據(jù)相關研究報道,，O₂的四極矩值小于N₂的三分之一,，因此其與極性基團的特定相互作用遠小于N₂。為了驗證此結論,，選用4種典型的多孔碳,，分別測在77k和87K下的O₂和N₂吸附，得到孔徑分布（PSD）與上述結論相一致,。本文中PSD（孔徑分布）計算采用了2D-NLDFT吸附模型,。

該文章的摘要如下：

The pore size distribution (PSD) of porous carbons is most often derived from the analysis of standard N₂ and Ar adsorption isotherms measured at 77 and 87?K. From the two gases, Ar is recommended (IUPAC Technical Report 2015) as more reliable for the PSD analysis due to its minimal specific interactions with the surface polar groups. Such interactions may influence the adsorption of N₂molecules due to its significant quadrupole moment. In practice, however, using liquid Ar as a cryogen for Ar adsorption measurements may be challenging because of its high cost and limited availability in various parts of the world. In this study, we propose using O₂ adsorption isotherms for the PSD characterization of porous carbons. The quadrupole moment of O₂ is less than one-third of the value reported for N₂, and thus its susceptibility to specific interactions with polar groups is much smaller than that of N₂. We demonstrate a quantitative agreement between the PSD results derived from the adsorption isotherms of O₂ and N₂ measured at 77?K, and Ar at 87?K on four representative carbon samples. The PSD calculations are performed using adsorption models based on the two-dimensional non-local density functional theory (2D-NLDFT).