Infrared spectroscopic and thermodynamic study on hydrogen adsorption on the metal organic framework MIL-100(Sc)

The thermodynamics of hydrogen interaction with coordinatively unsaturated ScIII cationic sites in the metal organic framework MIL-100(Sc) was studied by variable temperature infrared spectroscopy. Simultaneous measurement of the hydrogen equilibrium pressure (inside a closed IR cell) and the integrated IR absorbance over the temperature range 80–125 K led to the determination of the corresponding values of standard adsorption enthalpy and entropy, which resulted to be ΔH0 = −11.2 (±1) kJ mol−1 and ΔS0 = −120 (±10) J mol−1 K−1. The enthalpy value is among the largest reported so far for hydrogen adsorption on MOFs.