FTIR spectroscopic and computational studies on hydrogen adsorption on the zeolite Li-FER

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 4090 cm(-1). Three differential site types with respect to H-2 adsorption were found in the zeolite, two of which adsorb H-2. 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 Delta H-0 = -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.