ENCAPSULATION OF MOLECULAR-HYDROGEN IN ZEOLITES AT 1-ATM

About 1 μmol/g of molecular H2 is encapsulated in the sodalite cages of NaX zeolite at 37°C and 1 bar H2 pressure. The removal of this hydrogen by diffusion can be studied by temperature programming between 40 and 150°C under 1 bar Ar gas. The activation energy for diffusion is 8.1 kcal/mol. The amount of H2 trapped is more than an order of magnitude less than that expected for chemisorption on a catalyst like cobalt on NaX. Exchanging Cs+, Ni2+, and Eu3+ for Na+ cations into the supercages, hexagonal prisms, and sodalite cages, respectively, of X zeofite, leads to the conclusion that H2 is trapped in the sodalite cages. © 1990.