High-throughput computational screening of Cu-MOFs with open metal sites for efficient C2H2/C2H4 separation

• Main Authors: Lei Liu, Lei Wang, Dahuan Liu, Qingyuan Yang, Chongli Zhong
• Format: Article
• Language: English
• Published: KeAi Communications Co., Ltd. 2020-07-01
• Series: Green Energy & Environment
• Subjects: Acetylene and ethylene; Metal-organic frameworks; Open metal sites; Large-scale computation; Materials design
• Online Access: http://www.sciencedirect.com/science/article/pii/S2468025720300212

Cost effective separation of acetylene (C2H2) and ethylene (C2H4) is of key importance to obtain essential chemical raw materials for polymer industry. Due to the low compression limit of C2H2, there is an urgent demand to develop suitable materials for efficiently separating the two gases under ambient conditions. In this paper, we provided a high-throughput screening strategy to study porous metal-organic frameworks (MOFs) containing open metal sites (OMS) for C2H2/C2H4 separation, followed by a rational design of novel MOFs in-silico. A set of accurate force fields was established from ab initio calculations to describe the critical role of OMS towards guest molecules. From a large-scale computational screening of 916 experimental Cu-paddlewheel-based MOFs, three materials were identified with excellent separation performance. The structure-performance relationships revealed that the optimal materials should have the largest cavity diameter around 5–10 Å and pore volume in-between 0.3-1.0 cm3 g−1. Based on the systematic screening study result, three novel MOFs were further designed with the incorporation of fluorine functional group. The results showed that Cu-OMS and the –F group on the aromatic rings close to Cu sites could generate a synergistic effect on the preferential adsorption of C2H2 over C2H4, leading to a remarkable improvement of C2H2 separation performance of the materials. The findings could provide insight for future experimental design and synthesis of high-performance nanostructured materials for C2H2/C2H4 separation.