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Predicting adsorption enthalpies on silicalite and HZSM-5: A benchmark study on DFT strategies addressing dispersion interactions

Authors

  • Cheng-chau Chiu,

    1. Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore, Singapore
    2. Department Chemie and Catalysis Research Center, Technische Universität München, Garching, Germany
    3. Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research, Jurong Island, Singapore, Singapore
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  • Georgi N. Vayssilov,

    1. Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore, Singapore
    2. Faculty of Chemistry and Pharmacy, University of Sofia, Sofia, Bulgaria
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  • Alexander Genest,

    1. Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore, Singapore
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  • Armando Borgna,

    1. Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research, Jurong Island, Singapore, Singapore
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  • Notker Rösch

    Corresponding author
    1. Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore, Singapore
    2. Department Chemie and Catalysis Research Center, Technische Universität München, Garching, Germany
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Abstract

We evaluated the accuracy of periodic density functional calculations for adsorption enthalpies of water, alkanes, and alcohols in silicalite and HZSM-5 zeolites using a gradient-corrected density functional with empirical dispersion corrections (PBE-D) as well as a nonlocal correlation functional (vdW-DF2). Results of both approaches agree in acceptable fashion with experimental adsorption energies of alcohols in silicalite, but the adsorption energies for n-alkanes in both zeolite models are overestimated, by 21−46 kJ mol−1. For PBE-D calculations, the adsorption of alkanes is exclusively determined by the empirical dispersion term, while the generalized gradient approximation-DFT part is purely repulsive, preventing the molecule to come too close to the zeolite walls. The vdW-DF2 results are comparable to those of PBE-D calculations, but the latter values are slightly closer to the experiment in most cases. Thus, both computational approaches are unable to reproduce available experimental adsorption energies of alkanes in silicalite and HZSM-5 zeolite with chemical accuracy. © 2014 Wiley Periodicals, Inc.

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