Adsorption ofH2on carbon-based materials: A Raman spectroscopy study

Abstract

We made use of the Raman spectroscopy to investigate the mechanism of hydrogen adsorption on carbon materials. We have recorded the Raman active roto-vibrational Q branch of adsorbed hydrogen at various temperatures and pressures and we have developed a qualitatively theoretical model for the interpretation of the spectra. Because of the small Raman shifts observed for the Q branch we conclude that no charge transfer phenomena are involved in the interaction with the adsorbing material, but only a simple physisorption takes place; moreover, no C -H stretching signals in the region of ͑2800-3300͒ were detected, thus indicating that chemisorption, if any, should be negligible.

Hydrogen Adsorption on Metal Organic Framework Materials for Storage Applications

“…[192] Raman spectroscopy has also been used to study the adsorbed hydrogen phase in porous materials at room temperature and under cryogenic conditions. [220][221][222] The results confirm that the interaction strength for adsorption of molecular hydrogen is small and consistent with physisorption for single-walled nanotubes, MOF-5 and HKUST-1.…”

Hierarchically Controlled Helical Graphite Films Prepared from Iodine-Doped Helical Polyacetylene Films Using Morphology-Retaining Carbonization

“…They have been used in various applications, such as electrochemical energy storage, 1,3 fuel-and photovoltaiccell electrodes, 4,5 field-effect transistors, 4,6 catalyst supports, 7 and wear-resistant coatings. 8 A large number of chemical approaches have been reported for preparing carbon films that consist of evaporated amorphous carbons, 3 graphene-based materials, 4,9 and randomly networked or macroscopically aligned carbon nanotubes (CNTs). 10 It is well-known that a freestanding graphite film can be prepared from an aromatic polymer film, such as a commercially available polyimide film, by carbonization and graphitization at high temperature and normal pressure.…”

Development of Doped Nanoporous Carbons for Hydrogen Storage

“…33 Similarly, physisorption of hydrogen on amorphous carbon at 150 K and hydrogen pressures up to 64 bar perturbs it by 1-2 cm -1 . 34 The energetics of the shift appear to depend on the nature of the carbon binding sites, as no consistent trends are found in the above papers. The H 2 is more affected as hydrogen becomes incorporated or caged within a solid: Hydrogen present in silicon dislocations ('platelets') is perturbed by ~4 cm -1 , whereas H 2 incorporated at tetrahedral interstitial sites within crystalline silicon is shifted more than 500 cm -1 .…”

“…The H 2 is more affected as hydrogen becomes incorporated or caged within a solid: Hydrogen present in silicon dislocations ('platelets') is perturbed by ~4 cm -1 , whereas H 2 incorporated at tetrahedral interstitial sites within crystalline silicon is shifted more than 500 cm -1 . 35 The above studies were performed either at high-pressure and cryogenic temperatures, 33,34 or after treatment in a hydrogen plasma. 35 The high wavenumber Raman feature after reactive milling (Figure 14c) is in close proximity to that observed for molecular H 2 (Figure 14a).…”