Variable temperature FT-IR studies on hydrogen adsorption on the zeolite (Mg,Na)-Y

Variable-temperature infrared spectroscopy was used for the thermodynamic studies on the adsorption of hydrogen on the zeolite (Mg,Na)-Y. Adsorption renders the H–H stretching mode infrared active, and simultaneous measurement of IR absorbance and hydrogen equilibrium pressure, over a range of temperature, allowed adsorption enthalpy and entropy to be determined. The standard adsorption enthalpy and entropy resulted to be DH8 = 18.2( 0.8) kJ mol 1 and DS8 = 136( 10) J mol 1 K 1, respectively. The adsorption enthalpy is substantially higher than the hydrogen liquefaction heat, which suggests that magnesium-containing porous materials are potential candidates in the search for suitable adsorbents for reversible hydrogen storage.