Thermodynamics of Methane Adsorption on Copper HKUST-1 at Low Pressure.
Thermodynamics of Methane Adsorption on Copper HKUST-1 at Low Pressure.
复制标题
DOI：
10.1021/acs.jpclett.5b00893
复制
发表时间：
2015-06
期刊：
影响因子：
--
通讯作者：
Di Wu;Xiaofeng Guo;Hui Sun;A. Navrotsky
中科院分区：
文献类型：
--
作者：
Di Wu;Xiaofeng Guo;Hui Sun;A. Navrotsky
金属有机骨架（mof）可以通过调整孔隙结构和表面特性来设计成天然气储存材料。本文报道了在25°C、低压（低于1 bar）条件下，使用气体吸附量热法直接测量桨轮MOF （Cu HKUST-1）上CH4的吸附焓。在此压力区，CH4-CH4分子间相互作用最小，能量学仅反映CH4-MOF相互作用。我们的结果表明，适度的放热物理吸附，焓为-21.1±1.1 kJ/mol CH4，与覆盖无关。这个量热研究补充了以前的计算和晶体学研究，提供了零覆盖焓的CH4吸附。对新数据和文献数据的分析表明，在吸附的初始阶段，CH4-HKUST-1相互作用对孔隙尺寸比客体极化率更敏感，这表明开放Cu位点的化学结合作用不太特异性。
Metal-organic frameworks (MOFs) can be engineered as natural gas storage materials by tuning the pore structures and surface properties. Here we report the direct measurement of CH4 adsorption enthalpy on a paddlewheel MOF (Cu HKUST-1) using gas adsorption calorimetry at 25 °C at low pressures (below 1 bar). In this pressure region, the CH4-CH4 intermolecular interactions are minimized and the energetics solely reflects the CH4-MOF interactions. Our results suggest moderately exothermic physisorption with an enthalpy of -21.1 ± 1.1 kJ/mol CH4 independent of coverage. This calorimetric investigation complements previous computational and crystallographic studies by providing zero coverage enthalpies of CH4 adsorption. The analysis of the new and literature data suggests that in initial stages of adsorption the CH4-HKUST-1 interaction tends to be more sensitive to the pore dimension than to the guest polarizability, suggesting a less specific chemical binding role for the open Cu site.