| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 72683 | Microporous and Mesoporous Materials | 2014 | 11 Pages |
•The upper Si/Al limit of 3.8 is first estimated for carbonate formation in zeolites.•The larger heat of hydrogen carbonate formation is shown compared to carbonates.•The drift of alkali cations upon carbonate influence is illustrated.•It is observed that RHO distortions are stimulated by alkali cations and carbonates.
The alkali forms of MeRHO zeolite (Me = Li, Na, K, Cs) are studied theoretically at the DFT/PBE level using projector augmented wave method (PAW) and periodic boundary conditions (PBC). The equilibrium positions of the Me cations have been optimized at the D8R prisms where they control molecular transport in the pores of MeRHO. The effect of the displacement of alkali cations has been estimated due to coordination of both carbonate or hydrogen carbonate anions that can also induce RHO framework transformations. Admitting the CO3−2 and HCO3− formations via the reactions between H2O and CO2, the energy of respective reactions was evaluated at various Si/Al moduli and analyzed regarding possible influence on the gas adsorption.
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