posted on 2024-03-13, 05:34authored byIlya V. Yakovlev, Aleksandr A. Shubin, Evgeniy S. Papulovskiy, Alexander V. Toktarev, Olga B. Lapina
Lateral (adsorbate–adsorbate) interactions between
adsorbed
molecules affect various physical and chemical properties of microporous
adsorbents and catalysts, influencing their functional properties.
In this work, we studied the hydration of microporous AlPO4-11 aluminophosphate, which has an unusually ordered structure upon
adsorption of water vapor, and according to 27Al NMR data,
only tetrahedrally or octahedrally coordinated Al sites are present
in the AlPO4-11. These 27Al NMR data are consistent
with the results of density functional theory (DFT) calculations of
hydrated AlPO4-11, which revealed the presence of a strong
repulsive lateral interaction at the initial stage of adsorption,
suppressing the adsorption of water on neighboring (separated by one
−O–P–O– bridge) Al crystallographic sites.
As a result, of all the different aluminum sites, only half of the
Al1 sites adsorb two water molecules and acquire octahedral coordination.