Introduction of π-complexation into porous aromatic framework for highly selective adsorption of ethylene over ethane

In this work, we demonstrate for the first time the introduction of π-complexation into a porous aromatic framework (PAF), affording significant increase in ethylene uptake capacity, as illustrated in the context of Ag(I) ion functionalized PAF-1, PAF-1-SO3Ag. IAST calculations using single-component-isotherm data and an equimolar ethylene/ethane ratio at 296 K reveal that PAF-1-SO3Ag shows exceptionally high ethylene/ethane adsorption selectivity (Sads: 27 to 125), far surpassing benchmark zeolite and any other MOF reported in literature. The formation of π-complexation between ethylene molecules and Ag(I) ions in PAF-1-SO 3Ag has been evidenced by the high isosteric heats of adsorption of C2H4 and also proved by in situ IR spectroscopy studies. Transient breakthrough experiments, supported by simulations, indicate the feasibility of PAF-1-SO3Ag for producing 99.95%+ pure C 2H4 in a Pressure Swing Adsorption operation. Our work herein thus suggests a new perspective to functionalizing PAFs and other types of advanced porous materials for highly selective adsorption of ethylene over ethane. © 2014 American Chemical Society.

Li, B., Zhang, Y., Krishna, R., Yao, K., Han, Y., Wu, Z., … Ma, S. (2014). Introduction of π-Complexation into Porous Aromatic Framework for Highly Selective Adsorption of Ethylene over Ethane. Journal of the American Chemical Society, 136(24), 8654–8660. doi:10.1021/ja502119z

The authors acknowledge the University of South Florida for financial support of this work, and an award from the National Science Foundation (DMR-1352065) is also acknowledged. Part of the work including the in situ IR studies was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facility Division, Office of Basic Energy Sciences (BES), U.S. Department of Energy (DOE). DOE/BES/Division of Materials Sciences and Engineering (Award No. KC020105-FWP12152) (P.K.T.) and the National Natural Science Foundation of China (No. 21371069) (Z.S.) are acknowledged. We thank Prof. Jeffrey R. Long and Eric Bloch for their kind help on the calculation of regeneration energies.

American Chemical Society (ACS)

Journal of the American Chemical Society


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