Overcoming the Trade‐Off between C2H2 Sorption and Separation Performance by Regulating Metal‐Alkyne Chemical Interaction in Metal‐Organic Frameworks

• Published in: Angewandte Chemie International Edition 2023-05, Vol.62 (22), p.n/a
• Main Authors: Tan, Yan‐Xi, Lin, Jing, Li, Qiao‐Hong, Li, Liqiong, Anil Borse, Rahul, Lu, Weigang, Wang, Yaobing, Yuan, Daqiang
• Format: Article
• Language: English
• Subjects: Acetylene Capture; Alkynes; Breakthrough Experiment; Carbon dioxide; Chemical reactions; Copper; Covalent bonds; Metal-Alkyne Chemistry; Metal-Organic Framework; Metal-organic frameworks; Metals; Niobium oxides; Palladium; Platinum; Porous materials; Separation; Sorption; Sorption and Separation
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202302882

Designing porous materials for C2H2 purification and safe storage is essential research for industrial utilization. We emphatically regulate the metal‐alkyne interaction of PdII and PtII on C2H2 sorption and C2H2/CO2 separation in two isostructural NbO metal–organic frameworks (MOFs), Pd/Cu‐PDA and Pt/Cu‐PDA. The experimental investigations and systematic theoretical calculations reveal that PdII in Pd/Cu‐PDA undergoes spontaneous chemical reaction with C2H2, leading to irreversible structural collapse and loss of C2H2/CO2 sorption and separation. Contrarily, PtII in Pt/Cu‐PDA shows strong di‐σ bond interaction with C2H2 to form specific π‐complexation, contributing to high C2H2 capture (28.7 cm3 g−1 at 0.01 bar and 153 cm3 g−1 at 1 bar). The reusable Pt/Cu‐PDA efficiently separates C2H2 from C2H2/CO2 mixtures with satisfying selectivity and C2H2 capacity (37 min g−1). This research provides valuable insight into designing high‐performance MOFs for gas sorption and separation. The metal‐alkyne chemical interaction of PdII and PtII in two isostructural NbO metal–organic frameworks was regulated to obtain different binding affinities for C2H2. As a result, C2H2 could be selectively adsorbed and C2H2/CO2 could be separated at ambient conditions.