Precise Pore Space Partitions Combined with High‐Density Hydrogen‐Bonding Acceptors within Metal–Organic Frameworks for Highly Efficient Acetylene Storage and Separation
Yingying Xue, Xiao‐Ying Bai, Jing Zhang, Ying Wang, Shu‐Ni Li, Yu‐Cheng Jiang, Man‐Cheng Hu, Quan‐Guo Zhai
Abstract
Abstract The high storage capacity versus high selectivity trade‐off barrier presents a daunting challenge to practical application as an acetylene (C 2 H 2 ) adsorbent. A structure–performance relationship screening for sixty‐two high‐performance metal–organic framework adsorbents reveals that a moderate pore size distribution around 5.0–7.5 Å is critical to fulfill this task. A precise pore space partition approach was involved to partition 1D hexagonal channels of typical MIL‐88 architecture into finite segments with pore sizes varying from 4.5 Å (SNNU‐26) to 6.4 Å (SNNU‐27), 7.1 Å (SNNU‐28), and 8.1 Å (SNNU‐29). Coupled with bare tetrazole N sites (6 or 12 bare N sites within one cage) as high‐density H‐bonding acceptors for C 2 H 2 , the target MOFs offer a good combination of high C 2 H 2 /CO 2 adsorption selectivity and high C 2 H 2 uptake capacity in addition to good stability. The optimized SNNU‐27‐Fe material demonstrates a C 2 H 2 uptake of 182.4 cm 3 g −1 and an extraordinary C 2 H 2 /CO 2 dynamic breakthrough time up to 91 min g −1 under ambient conditions.