在MOF-5中对吸附的初步研究
Kaido Sillar1, Alexander Hofmann, Joachim Sauer
1Institut für Chemie, Humboldt-Universität zu Berlin, Berlin, Germany.
Journal of the American Chemical Society
|March 4, 2009
概括
金属有机框架 (MOF) 显示出储存的潜力. 计算方法显示,最强的H2相互作用发生在特定的MOF-5地点,这对于预测存储容量至关重要.
科学领域:
- 材料科学 材料科学 材料科学
- 计算化学计算化学
- 化学工程是化学工程的重要组成部分.
背景情况:
- 金属有机框架 (MOF) 是一种先进的多孔材料,具有气体储存应用的巨大潜力.
- 有效的储存对于发展可持续能源经济至关重要.
- 了解和MOF结构之间的基本相互作用是设计最佳存储材料的关键.
研究的目的:
- 以计算方式研究分子 (H2) 与MOF-5框架之间的相互作用能量.
- 在MOF-5中确定特定的吸附部位,这些部位对H2具有最强的结合亲和力.
- 在MOF中开发吸附异热的预测模型.
主要方法:
- 使用密度函数理论 (DFT) 和二次莫勒-普莱塞特扰动理论 (MP2) 来计算相互作用能量.
- 用有限模型计算对整个MOF-5结构的周期性边界条件的结果进行比较.
- 采用Multi-Langmuir模型来模拟和预测吸附等热体.
主要成果:
- 最强的H2相互作用被确定在OZn4(O2Ph) 6节点的α位点,相互作用能量为-7.1 kJ/mol在77 K.
- 发现分散相互作用和零点振动能量对于准确的计算至关重要.
- 计算表明,吸附部位周围的局部环境主要影响H2相互作用.
- 基于MP2的Multi-Langmuir模型准确地复制了实验性吸附等温体,预测了在77K和40bar时6重量%的H2吸收,假设吸附的H2的旋转自由度保留了.
结论:
- 该研究强调了准确的理论方法的重要性,包括分散和振动能量,用于预测MOF中的吸附.
- 当地吸附点的特征显著决定了MOF-5中的结强度.
- 开发的计算方法提供了一种可靠的方法来区分不同的MOF样本,并预测新型MOF结构中的吸附行为.
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