Enhancing light hydrocarbon storage and separation through introducing Lewis basic nitrogen sites within a carboxylate-decorated copper–organic framework. (19th April 2018)

• Record Type: Journal Article
• Authors: Liu, Xiuping; Fan, Weidong; Zhang, Minghui; Li, Guixia; Liu, Haijun; Sun, Daofeng; Zhao, Lianming; Zhu, Houyu; Guo, Wenyue
• Is Part Of: Materials chemistry frontiers. Volume 2:Number 6(2018)
• Page Start: 1146
• Page End: 1154
• Publication Date: 2018-04-19
• Subjects: Materials science -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1039/c8qm00105g
• Languages: English
• ISSNs: 2052-1529

Abstract

Abstract : A novel copper–organic framework (NEM-4) with functional groups exhibits both outstanding C1 –C3 hydrocarbon uptakes and selectivities under ambient conditions. Abstract : A novel nanoporous Cu metal–organic framework (NEM-4) with open Cu II sites, Lewis basic nitrogen sites, and uncoordinated –COO − groups exhibits both outstanding uptake capacities (in cm 3 (STP) g −1 ) for C2 H2 (204), C2 H4 (164.1), C2 H6 (172.2), C3 H6 (197.4), and C3 H8 (196.1) and high selectivities for C2 H2 /CH4 (63.2), C3 H6 /CH4 (174.8), and C3 H8 /CH4 (168.3) under ambient conditions. After eight cycles of adsorption–desorption tests, only 8.2% and 10.3% decrease in the acetylene and propene storage capacities was observed, indicating an excellent repeatability. Compared with1 (carboxylate decorated NOTT-101), when nitrogen sites are inserted, the C2 –C3 hydrocarbon uptakes of NEM-4 can be significantly enhanced. Grand Canonical Monte Carlo and first-principles calculations reveal that not only the open Cu II sites but also the uncoordinated –COO − groups and the nitrogen sites play significant roles in its high C2 –C3 hydrocarbon uptakes. Moreover, the adsorption and separation of cationic dyes in NEM-4 are highly size and charge state dependent, and the adsorbed methylene blue (MB + ) in NEM-4 can be efficiently released in an NaCl-containing CH3 OH solution. This study reveals that the combination of open metal sites, carboxylate groups, Lewis basic pyridyl sites, and appropriate pore geometry is responsible for the high adsorption/separation of light hydrocarbons in NEM-4.