Identification of Intermediates during the Hydration of Na8[AlSiO4]6(BH4)2: A Combined Theoretical and Experimental Approach.

Abstract

Tetrahydroborate sodalites have been discussed as possible materials for reversible hydrogen storage. In order to access the suitability of Na8[AlSiO4]6(BH4)2, its reaction with water was investigated theoretically and experimentally. Density functional theory (DFT) calculations at the generalized gradient approximation (GGA) level were performed to identify the reaction intermediates. We compared experimental IR spectra and 11B NMR chemical shifts with theoretical results for selected molecules in the sodalite cage. Furthermore, the free energies of reaction of the intermediates with respect to Na8[AlSiO4]6(BH4)2, gaseous water, and molecular hydrogen at different temperatures were also calculated.