Chen Haonan, Saren Sagar, Liu Xuetao, Jeong Ji Hwan, Miyazaki Takahiko, Kim Young-Deuk, Thu Kyaw
Department of Advanced Environmental Science and Engineering, Faculty of Engineering Sciences, Kyushu University, Kasuga-koen 6-1, Kasuga, Fukuoka 816-8580, Japan.
Institute of Innovation for Future Society, Nagoya University, Furu-cho, Chikusa, Nagoya, Aichi 464-8603, Japan.
iScience. 2025 Mar 8;28(4):112181. doi: 10.1016/j.isci.2025.112181. eCollection 2025 Apr 18.
Physisorption of gases has been widely applied in thermal energy utilization and purification processes. Diffusion in porous media has been well studied. However, molecular-scale adsorbate diffusion mechanism remains unexplored. In this study, molecular dynamics have been employed to elucidate the diffusion behaviors of liquid and gaseous methane adsorbed in Cu-BTC (Copper(2+) 1,3,5-benzenetricarboxylate). Based on the energy distribution and trajectories of adsorbed molecules, a hypothesis is proposed that the adsorbed phase can be classified into four types: bound molecules (oscillate around a specific region of the adsorbent), generally adsorbed molecules (within the range of surface interaction and possess negative total energy), non-adsorbed molecules (within the range of surface interaction, but having positive total energy), and free molecules (beyond the range of surface interaction). To support this hypothesis, further simulation of methane adsorption in MOF-5 (ZnO(BDC)) has been conducted and compared with existing experimental data, indicating the hypothesis has broader applicability.
气体的物理吸附已广泛应用于热能利用和净化过程。多孔介质中的扩散已得到充分研究。然而，分子尺度的吸附质扩散机制仍未被探索。在本研究中，采用分子动力学来阐明吸附在Cu-BTC（铜（II）1,3,5-苯三甲酸酯）中的液态和气态甲烷的扩散行为。基于吸附分子的能量分布和轨迹，提出了一个假设，即吸附相可分为四种类型：束缚分子（在吸附剂的特定区域周围振荡）、一般吸附分子（在表面相互作用范围内且总能量为负）、未吸附分子（在表面相互作用范围内，但总能量为正）和自由分子（超出表面相互作用范围）。为了支持这一假设，对MOF-5（ZnO（BDC））中甲烷吸附进行了进一步模拟，并与现有实验数据进行了比较，表明该假设具有更广泛的适用性。
