A stable metal-organic framework with oxygen site for efficiently trapping acetylene from acetylene-containing mixtures

Highly selective separation of acetylene from various other gases (e.g., carbon dioxide and methane) is of great importance in the petrochemical industry but remains a challenge due to their similar sizes and physical properties. Herein, we reported a microporous metal − organic framework Zn 4 O(NTB) 2 (H 3 NTB = 4,4′,4″-nitrilotribenzoicacid acid), features oxygen binding sites explored for C 2 H 2 capture and separation. A high C 2 H 2 uptake of 2.62 mmol g −1 combined with excellent selectivity of C 2 H 2 /CO 2 (4.8) and C 2 H 2 /CH 4 (21.6) under ambient conditions (i.e., 50:50 mixture at 298 K and 1 bar) was realized. Moreover, the grand canonical Monte Carlo (GCMC) simulations and first-principles density functional theory (DFT) calculations have identified that the high C 2 H 2 capture and selectivity ascribe to oxygen sites on the pores (C–H…O interaction). Dynamic breakthrough experiments comprehensively demonstrate that Zn 4 O(NTB) 2 is a promising adsorbent for practical C 2 H 2 /CO 2 and C 2 H 2 /CH 4 separation.