Polarizable Force Fields for CO2 and CH4 Adsorption in M-MOF-74
Polarizable Force Fields for CO2 and CH4 Adsorption in M-MOF-74
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DOI：
10.1021/acs.jpcc.6b12052
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发表时间：
2017-03-02
影响因子：
3.7
通讯作者：
Vugt, Thijs J. H.
中科院分区：
文献类型：
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作者：
Becker, Tim M.;Heinen, Jurn;Vugt, Thijs J. H.
M-MOF-74 系列（M = Co、Cr、Cu、Fe、Mg、Mn、Ni、Ti、V 和 Zn）为众多与能源相关的气体分离应用提供了机会。 M-MOF-74的孔隙结构表现出高内表面积和异常大的吸附容量。 M-MOF-74 中吸附物分子的化学环境可以通过交换结构中的金属离子来调节。为了优化给定分离过程的材料，深入了解金属离子的选择如何影响与吸附分子的相互作用强度以及如何模拟这些相互作用至关重要。在这里，我们通过将所提出的极化力场与 DFT 计算中的轨道相互作用能进行比较，定量地强调了极化的重要性。计算了 CO2、CH4 及其在 M-MOF-74 中与所有 10 种金属离子的混合物的吸附等温线和吸附热。将结果与实验数据以及之前使用源自量子力学的不可极化力场的模拟结果进行比较。据我们所知，所开发的极化力场是迄今为止唯一试图覆盖如此大一组可能的金属离子的力场。对于大多数金属离子，我们的模拟与实验非常吻合，证明了我们的极化电势的有效性以及所采用方法的可转移性。
The family of M-MOF-74, with M = Co, Cr, Cu, Fe, Mg, Mn, Ni, Ti, V, and Zn, provides opportunities for numerous energy related gas separation applications. The pore structure of M-MOF-74 exhibits a high internal surface area and an exceptionally large adsorption capacity. The chemical environment of the adsorbate molecule in M-MOF-74 can be tuned by exchanging the metal ion incorporated in the structure. To optimize materials for a given separation process, insights into how the choice of the metal ion affects the interaction strength with adsorbate molecules and how to model these interactions are essential. Here, we quantitatively highlight the importance of polarization by comparing the proposed polarizable force field to orbital interaction energies from DFT calculations. Adsorption isotherms and heats of adsorption are computed for CO2, CH4, and their mixtures in M-MOF-74 with all 10 metal ions. The results are compared to experimental data, and to previous simulation results using nonpolarizable force fields derived from quantum mechanics. To the best of our knowledge, the developed polarizable force field is the only one so far trying to cover such a large set of possible metal ions. For the majority of metal ions, our simulations are in good agreement with experiments, demonstrating the effectiveness of our polarizable potential and the transferability of the adopted approach.