Nguyen T X, Bae J-S, Wang Y, Bhatia S K
Division of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane QLD 4072, Australia.
Langmuir. 2009 Apr 21;25(8):4314-9. doi: 10.1021/la900220g.
We deduce a new value for the potential well depth for the C-H2 interaction on the basis of experimental validations of isotherms of H2 and D2 predicted using independently characterized microstructural parameters. We use two carbons, one an activated carbon fiber whose structure has been recently characterized by us (Nguyen, T. X.; cohaut, N.; Bae, J.-S.; Bhatia, S. K. Langmuir 2008, 24, 7912) using hybrid reverse Monte Carlo simulation (HRMC) and the other the commercial Takeda 3A carbon molecular sieve whose pore size distribution is determined here from the 273 K CO2 adsorption isotherm. The conventional grand canonical Monte Carlo simulation technique incorporating a semiclassical Feynman and Hibbs (FH) potential approximation (FHGCMC) as well as path integral Monte Carlo calculations is employed to determine theoretical adsorption isotherms. It is found that curvature enhances the well depth for the LJ C-H2 interaction by a factor of 1.134 over that for a flat graphite surface, consistent with our recent study (Nguyen, T. X.; cohaut, N.; Bae, J.-S.; Bhatia, S. K. Langmuir 2008, 24, 7912). A value of the C-C well depth of 37.26 K, used for estimating the C-H2 well depth in conjunction with the Berthelot rules, with the Steele C-C well depth used for interaction with heavier gases (Ar, CO2 and CH4), leads to excellent agreement with experimental isotherms in all cases.
基于使用独立表征的微观结构参数预测的H₂和D₂等温线的实验验证，我们推导出了C-H₂相互作用势阱深度的新值。我们使用了两种碳，一种是活性炭纤维，其结构最近由我们（Nguyen, T. X.; cohaut, N.; Bae, J.-S.; Bhatia, S. K. Langmuir 2008, 24, 7912）通过混合反向蒙特卡罗模拟（HRMC）进行了表征，另一种是商业武田3A碳分子筛，其孔径分布在此由273 K CO₂吸附等温线确定。采用结合半经典费曼和希布斯（FH）势近似的传统巨正则蒙特卡罗模拟技术（FHGCMC）以及路径积分蒙特卡罗计算来确定理论吸附等温线。结果发现，与平坦石墨表面相比，曲率使LJ C-H₂相互作用的势阱深度增加了1.134倍，这与我们最近的研究（Nguyen, T. X.; cohaut, N.; Bae, J.-S.; Bhatia, S. K. Langmuir 2008, 24, 7912）一致。用于结合贝特洛规则估算C-H₂势阱深度的C-C势阱深度值为37.26 K，其中斯蒂尔C-C势阱深度用于与较重气体（Ar、CO₂和CH₄）相互作用，在所有情况下均与实验等温线达成了极佳的吻合。
