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arXiv 2307.04489cond-mat.mtrl-sci
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用于增强二氧化碳吸附的金属有机框架有机桥接连接体的设计

Designing of Organic Bridging Linkers of Metal-Organic Frameworks for Enhanced Carbon Dioxide Adsorption

Kahkasha Parveen, Srimanta Pakhira

AI总结:

本文通过分子簇模型和第一性原理计算研究多种MOF连接体对CO2的吸附,发现锂修饰可显著增强结合强度,其中DFBDC-2侧位吸附ΔH达-35.32 kJ/mol,为设计高效碳捕集吸附剂提供了指导。

摘要:

全球人为二氧化碳排放速率持续上升,这迫切需要开发高效的碳捕集与封存(CCS)技术。在各种二氧化碳捕集方法中,金属有机框架(MOFs)材料连接体的吸附因其作为优异二氧化碳吸附剂的重要作用而受到越来越多的关注,因为它们在理解二氧化碳吸附的相互作用机制中扮演着重要角色。在此,我们使用分子簇模型研究了二氧化碳分子在几种MOF连接体的中心位置和侧位位置上的吸附。二氧化碳与连接体之间的相互作用通过基于第一性原理的密度泛函理论(含Grimme色散校正,即B3LYP-D3)和二阶Møller-Plesset微扰理论(MP2)计算结合焓(ΔH)来近似。计算得到的ΔH值表明二氧化碳在原始连接体上的吸附具有弱吸附性质,因此采用锂修饰策略来考察其对结合强度的影响。在所测试的各种连接体中,二氧化碳吸附在DFBDC-2连接体的侧位位置上具有强吸附,由B3LYP-D3方法计算得到的ΔH值约为-35.32 kJ/mol。能量分解分析(EDA)研究表明,在所有能量项中,静电能量项和极化能量项对ΔH值的贡献最为主要。此外,前线分子轨道分析(FMO)的结果表明,所有连接体即使在锂修饰后仍保持稳定。我们的研究结果将指导具有增强二氧化碳吸附性能的新型吸附剂的开发和合成。

英文摘要:

The global rate of anthropogenic CO2 emission is rising, which urges the development of efficient carbon capture and storage (CCS) technologies. Among the various CO2 capture methods, adsorption by the linkers of the Metal-Organic Frameworks (MOFs) materials has received more interest as excellent CO2 adsorbents because of their important role in understanding the interaction mechanism for CO2 adsorption. Here, we investigate the adsorption of CO2 molecules at the center and side positions of several MOF-linkers using molecular cluster models. The interaction between CO2 and the linkers is approximated by computing the binding enthalpy (ΔH) through the first principles-based Density Functional Theory with Grimmes dispersion correction (i.e., B3LYP-D3) and second-order Moller Plesset Theory (MP2). The computed values of ΔH indicate the weak nature of CO2 adsorption on the pristine linkers, hence the strategy of lithium decoration is used to see its impact on the binding strength. Among the various linkers tested, CO2 adsorbing at the side position of the DFBDC-2 linker has strong adsorption with ΔH value of about -35.32 kJ/mol computed by the B3LYP-D3 method. The Energy Decomposition Analysis (EDA) study reveals that among all the energy terms, the contribution of electrostatic and polarization energy terms to the ΔH value are the most dominant one. Furthermore, the results of Frontier Molecular Orbital Analysis (FMO) revealed that all the linkers remained stable even after Li-decoration. The results of our investigations will direct towards the development and synthesis of novel adsorbents with enhanced CO2 adsorption.

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