abstract
The adsorptions of ethane, ethene, and ethyne over the coordinatively unsaturated sites (CUS) of copper (II) benzene-1,3,5-tricarboxylate (CuBTC) were studied by means of density functional theory (DFT), using both cluster or periodic models. Exchange-correlation functionals from different rungs of the Jacobs ladder of the DFT were used and energies were corrected for the basis superposition error either through extrapolation to the complete basis set limit or upon the consideration of the Counterpoise method. From the calculated data, it was found that the adsorbate to CUS distances decrease in the order ethane > ethene approximate to ethyne and that the strength of adsorption increase in the order ethane to ethyne to ethene. The energies of interactions of ethene and ethyne with the CUS of CuBTC are approximately the double of that calculated for ethane. The calculated adsorption energies and geometries are in very satisfactory agreement with the available experimental results. The results of topological analyses confirm that the unsaturated bonds of ethene and ethyne form open shell like bonds with the CUS while interaction with ethane have predominant closed shell character.
keywords
METAL-ORGANIC FRAMEWORKS; CORRELATED MOLECULAR CALCULATIONS; CONSISTENT BASIS-SETS; GAUSSIAN-BASIS SETS; OPEN COPPER SITES; ADSORPTIVE SEPARATION; PROPANE/PROPYLENE SEPARATION; LIGHT-HYDROCARBONS; ACETYLENE STORAGE; SWING ADSORPTION
subject category
Materials Science
authors
Afonso, R; Toda, J; Gomes, JRB; Fischer, M; Campbell, C; Jorge, M
our authors
José R. B. Gomes
Principal Researcheracknowledgements
This work was developed in the scope of the projects CICECO-Aveiro Institute of Materials POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2019) and Smart Green Homes POCI-01-0247-FEDER-007678, a co-promotion between Bosch Termotecnologia S.A. and the University of Aveiro. These projects are financed by Portugal 2020 under the Competitiveness and Internationalization Operational Program and by the European Regional Development Fund (FEDER).