Raman studies of hydrogen adsorbed on nanostructured porous materials

Abstract

Raman spectroscopy was applied to study the adsorbed hydrogen phase in porous materials at room temperature and under cryogenic conditions. A comparison between the Raman spectra of H₂ molecules adsorbed on single walled carbon nanotubes and on a Cu-based metal–organic framework reveals that the interaction strength for the adsorption of molecular hydrogen is very similar in these materials. In both cases the small perturbation of the Raman spectrum of hydrogen indicates that adsorption takes place without any evident charge transfer between H₂ and the adsorbent. Additionally for single walled carbon nanotubes at least two types of adsorption sites could be identified by Raman spectroscopy.