PORE-SIZE HETEROGENEITY AND THE CARBON SLIT PORE - A DENSITY-FUNCTIONAL THEORY MODEL
PORE-SIZE HETEROGENEITY AND THE CARBON SLIT PORE - A DENSITY-FUNCTIONAL THEORY MODEL
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DOI：
10.1021/la00034a032
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发表时间：
1993-10-01
期刊：
影响因子：
3.9
通讯作者：
QUIRKE, N
中科院分区：
文献类型：
--
作者：
LASTOSKIE, C;GUBBINS, KE;QUIRKE, N
提出了非局域密度泛函理论预测的简单流体在碳缝孔中吸附的模型等温线。考察了孔大小、温度和固-流势相互作用强度的影响。我们的结果被总结为一种基于连续孔隙填充、毛细管冷凝和0-->；1分层转变的分类方案。我们设计的描述与IUPAC惯例不同，因为填充行为而不是毛孔的物理宽度被用作分类的指南。我们的结果表明，虽然固体-流体相互作用的大小决定了发生孔填充的压力，但填充的类型主要取决于孔宽度与吸附分子直径的比率。表明各种填充行为之间的边界的临界孔宽强烈地依赖于温度。为了验证理论结果的准确性，我们比较了非局域理论和Gibbs系综模拟计算的吸附等温线和密度分布。理论计算结果与仿真结果吻合较好。最后，我们讨论了从实验中估计用于理论计算的固体-流体势参数的相关问题。对非局域理论模型等温线与实验测得的非孔炭吸氮量进行了比较。
We present model isotherms predicted by nonlocal density functional theory for adsorption of simple fluids in carbon slit pores. The effects of pore size, temperature, and solid-fluid potential interaction strength are examined. Our results are summarized into a classification scheme based upon regimes of continuous pore filling, capillary condensation, and 0 --> 1 layering transitions. The descriptions we have devised depart from the IUPAC convention in that the filling behavior, rather than the physical width of the pore, is used as a guide to classification. Our results suggest that while the magnitude of the solid-fluid interactions dictates the pressure at which pore filling occurs, the type of filling depends primarily upon the ratio of pore width to adsorbate molecular diameter. The critical pore widths that denote the boundaries between various regimes of filling behavior are strongly dependent upon the temperature. To confirm the accuracy of the theoretical results, we compare adsorption isotherms and density profiles calculated from nonlocal theory and Gibbs ensemble simulation. The results from theory and simulation are found to be in good agreement. We conclude with a discussion of the problems associated with estimating solid-fluid potential parameters from experiment for use in theoretical computations. A comparison of nonlocal theory model isotherms and experimental nitrogen uptake measurements on nonporous carbon is presented.