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 Na[AlSiO](BH), 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 B 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 Na[AlSiO](BH), gaseous water, and molecular hydrogen at different temperatures were also calculated.