Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur GraphSearch.
For different hydrogenated metal intercalated fullerides (Na10C60-H, Li12C60-H, and Li28C60-H) the activation energies for hydrogen desorption were determined by DSC. The Vyazovkin advanced method (VA) was used for the calculation of the reaction model free activation energy as a function of the extent of conversion a. Activation energies are highest for low a and decrease for increasing alpha, between around 200-145 and 245-175 kJ/mol for the Na and Li compounds, respectively. The decrease of activation energy as a function of the extent of conversion can be explained by an increasing charge transfer to the C60H36+y cage during desorption. Na intercalation leads to a significant thermodynamic destabilization for hydrogen desorption. Dehydrogenation enthalpies of 52 (Na10C60-H), 66 (Li12C60-H), and 69 kJ/mol H-2 (Li28C60-H) were determined. These values are lower compared to literature values for desorption of pure C60H36 (74 kJ/mol H-2). The onsets of hydrogen desorption are 185 degrees C (Na10C60-H), 260 degrees C (Li12C60-H), and 250 degrees C (Li28C60-H) compared to >400 degrees C for pure C60H36.
Chargement
Chargement
Aucun résultat