Microporous mixed-metal mixed-ligand metal organic framework for selective CO2 capture. Issue 39 (27th September 2018)

• Record Type: Journal Article
• Authors: Maity, Rahul; Chakraborty, Debanjan; Nandi, Shyamapada; Rinku, Kushwaha; Vaidhyanathan, Ramanathan
• Is Part Of: CrystEngComm. Volume 20:Issue 39(2018)
• Page Start: 6088
• Page End: 6093
• Publication Date: 2018-09-27
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/c8ce00752g
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : Layered-pillared framework of the CO2 -loaded MOF developed using this mixed-metal mixed-ligand approach showing the multiple-adsorption sites within the MOF. Abstract : A microporous mixed-ligand-based metal–organic framework has been synthesized using two different dicarboxylic acid-based ligands (4, 4′-biphenyldicarboxylate (BPDC) and imino diacetate (IMDA)) and two different metal ions (Ce 3+ and Na + ), namely Ce3 Na3 (BPDC)3 (IMDA)3 ·(DMF)2 (H2 O)9 . The framework built from Ce–Na–carboxylate layers and BPDC pillars consists of 2D slit-shaped pores occupied by extra-framework Na + ions. The desolvated framework is permanently porous with a BET surface area of ∼771 m 2 g −1 and displays moderate CO2 uptake of 2.0 mmol g −1 with a CO2 /N2 selectivity ( S ) of 68 at room temperature and 1 bar. A modest heat of adsorption (23 kJ mol −1 ) and smooth diffusion kinetics are observed, as reflected in the facile CO2 cycling. Using GCMC methods, the CO2 adsorption isotherm at 298 K was simulated, which matches the experimental isotherm well. The CO2 positions observed from the simulations showed that Na + ions in the channels serve as favorable adsorption sites for the oxygen atoms in CO2 pointing toward the Na + ions (OCO⋯Na + = 3.34–5.87 Å), while some CO2 molecules sit flat on the phenyl rings of the BPDC at a CO2 ⋯centroid distance of 3.6–3.7 Å.