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

Abstract

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 80–125K led to the determination of the corresponding values of standard adsorption enthalpy and entropy, which resulted to be ΔH0=−11.2 (±1)kJmol−1 and ΔS0=−120 (±10)Jmol−1K−1. The enthalpy value is among the largest reported so far for hydrogen adsorption on MOFs.