A Universal Descriptor for the Entropy of Adsorbed Molecules in Confined Spaces

Paul J. Dauenhauer, Omar A. Abdelrahman

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Confinement of hydrocarbons in nanoscale pockets and pores provides tunable capability for controlling molecules in catalysts, sorbents, and membranes for reaction and separation applications. While computation of the enthalpic interactions of hydrocarbons in confined spaces has improved, understanding and predicting the entropy of confined molecules remains a challenge. Here we show, using a set of nine aluminosilicate zeolite frameworks with broad variation in pore and cavity structure, that the entropy of adsorption can be predicted as a linear combination of rotational and translational entropy. The extent of entropy lost upon adsorption is predicted using only a single material descriptor, the occupiable volume (Vocc). Predictive capability of confined molecular entropy permits an understanding of the relation with adsorption enthalpy, the ability to computationally screen microporous materials, and an understanding of the role of confinement on the kinetics of molecules in confined spaces.

Original languageEnglish (US)
Pages (from-to)1235-1243
Number of pages9
JournalACS Central Science
Volume4
Issue number9
DOIs
StatePublished - Sep 26 2018

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