FTIR Spectroscopic and Computational Studies on Hydrogen Adsorption on the Zeolite Li–FER

Abstract

The interaction, at a low temperature, between molecular hydrogen and the zeolite Li–FER was studied by means of variable temperature infrared spectroscopy and theoretical calculations using a periodic DFT model. The adsorbed dihydrogen molecule becomes infrared active, giving a characteristic IR absorption band (H–H stretching) at 4090cm–1. Three different Li+ site types with respect to H2 adsorption were found in the zeolite, two of which adsorb H2. Calculations showed a similar interaction energy for these two sites, which was found to agree with the experimentally determined value of standard adsorption enthalpy of H0=–4.1(±0.8)kJ.mol–1. The results are discussed in the broader context of previously reported data for H2 adsorption on Na–FER and K–FER.