Near-Perfect CO2/CH4 Selectivity Achieved through Reversible Guest Templating in the Flexible Metal-Organic Framework Co(bdp)
- 14 August 2018
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 140 (32), 10324-10331
- https://doi.org/10.1021/jacs.8b06062
Abstract
Metal organic frameworks are among the most promising materials for industrial gas separations, including the removal of carbon dioxide from natural gas, although substantial improvements in adsorption selectivity are still sought. Herein, we use equilibrium adsorption experiments to demonstrate that the flexible metal organic framework Co(bdp) (bdp(2-) = 1,4-benzenedipyrazolate) exhibits a large CO2 adsorption capacity and approaches complete exclusion of CH4 under 50:50 mixtures of the two gases, leading to outstanding CO2/CH4 selectivity under these conditions. In situ powder X-ray diffraction data indicate that this selectivity arises from reversible guest templating, in which the framework expands to form a CO2 clathrate and then collapses to the nontemplated phase upon desorption. Under an atmosphere dominated by CH4, Co(bdp) adsorbs minor amounts of CH4 along with CO2, highlighting the importance of studying all relevant pressure and composition ranges via multicomponent measurements when examining mixed-gas selectivity in structurally flexible materials. Altogether, these results show that Co(bdp) may be a promising CO2/CH4 separation material and provide insights for the further study of flexible adsorbents for gas separations.Funding Information
- Basic Energy Sciences (DE-AC02-06CH11357, DE-SC0001015)
- Fuel Cell Technologies Office (DE-AC36-08GO28308)
- National Science Foundation (Graduate Research Fellowships awarded to M.K.T., J)
This publication has 54 references indexed in Scilit:
- Flexibility in Metal-Organic Frameworks: A fundamental understandingCoordination Chemistry Reviews, 2018
- CO2 Capture and Separations Using MOFs: Computational and Experimental StudiesChemical Reviews, 2017
- Seven chemical separations to change the worldNature, 2016
- Stepping on the gasScience, 2014
- Flexible metal–organic frameworksChemical Society Reviews, 2014
- Current status and development of membranes for CO2/CH4 separation: A reviewInternational Journal of Greenhouse Gas Control, 2012
- The removal of CO2 and N2 from natural gas: A review of conventional and emerging process technologiesJournal of Petroleum Science and Engineering, 2012
- Soft porous crystalsNature Chemistry, 2009
- Selective gas adsorption and separation in metal–organic frameworksChemical Society Reviews, 2009
- Flexible (Breathing) Interpenetrated Metal−Organic Frameworks for CO2 Separation ApplicationsJournal of the American Chemical Society, 2008