Ab Initio Adsorption Isotherms for Molecules with Lateral Interactions: CO2 in Metal–Organic Frameworks
Ab Initio Adsorption Isotherms for Molecules with Lateral Interactions: CO2 in Metal–Organic Frameworks
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DOI：
10.1021/acs.jpcc.7b02806
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发表时间：
2017-06
影响因子：
3.7
通讯作者：
Kaido Sillar;Arpan Kundu;J. Sauer
中科院分区：
文献类型：
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作者：
Kaido Sillar;Arpan Kundu;J. Sauer
研究了金属有机骨架CPO-27-Mg （Mg-MOF-74）对二氧化碳的吸附。我们使用精确的量子化学从头算方法（簇模型的波函数型电子相关方法结合周期系统的密度泛函理论）来计算气-气表面位置和气-气相互作用。在298 K时，CO2在Mg2+位点上的零覆盖焓和吉布斯自由能分别为- 46和- 9 kJ/mol；对于连接位点，这些值分别为- 30和+5 kJ/mol。对于完全覆盖的单层，来自附近分子的横向相互作用分别对Mg2+和连接体位点的CO2吸附焓贡献- 6和- 5 kJ/mol。预测的吸附热和吸附自由能分别在2.6 kJ/mol和0.8 kJ/mol之间，实验值完全符合化学精度限制（4.2 kJ/mol）。我们用两种不同的方法从平衡常数和相互作用能计算等温线：(i)…
Adsorption of carbon dioxide in the metal–organic framework CPO-27-Mg (Mg-MOF-74) is examined. We use accurate quantum chemical ab initio methods (wave function-type electron correlation methods for cluster models combined with density functional theory for periodic systems) to calculate gas–surface site and gas–gas interactions. At 298 K, the “zero-coverage” enthalpy and Gibbs free energy of CO2 adsorption on Mg2+ sites are −46 and −9 kJ/mol, respectively; for linker sites these values are −30 and +5 kJ/mol, respectively. For full monolayer coverage lateral interactions from nearby molecules contribute −6 and −5 kJ/mol to the adsorption enthalpy for CO2 at Mg2+ and linker sites, respectively. The predicted heats of adsorption and free energies of adsorption agree within 2.6 and 0.8 kJ/mol, respectively, with experimental values well within chemical accuracy limits (4.2 kJ/mol). We use two different ways of calculating isotherms from equilibrium constants for individual sites and interaction energies: (i)...