title: N-doped carbon networks: alternative materials tracing new routes for activating molecular hydrogen.
abstract: The fragmentation of molecular hydrogen on N-doped carbon networks was investigated by using molecular (polyaromatic macrocycles) as well as truncated and periodic (carbon nanotubes) models. The computational study was focused on the ergonicity analysis of the reaction and on the properties of the transition states involved when constellations of three or four pyridinic nitrogen atom defects are present in the carbon network. Calculations show that whenever N-defects are embedded in species characterized by large conjugated π-systems, either in polyaromatic macrocycles or carbon nanotubes, the corresponding H2 bond cleavage is largely exergonic. The fragmentation Gibbs free energy is affected by the final arrangement of the hydrogen atoms on the defect and by the extension of the π-electron cloud, but it is not influenced by the curvature of the system.
authors.affiliation: Dipartimento di Fisica e Chimica dell'Università degli Studi di Palermo, Viale delle Scienze Ed. 17, 90128 Palermo (Italy).
authors.forename: Remedios
authors.initials: R
authors.lastname: Cortese
authors.forename: Francesco
authors.initials: F
authors.lastname: Ferrante
authors.forename: Stefan
authors.initials: S
authors.lastname: Roggan
authors.forename: Dario
authors.initials: D
authors.lastname: Duca
mesh_terms: D002244:Carbon / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008958:Models, Molecular; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*
chemical_list: D047028:Macrocyclic Compounds; D037742:Nanotubes, Carbon; D002244:Carbon; D006859:Hydrogen; D009584:Nitrogen
keywords: carbon networks; density functional calculations; doping; hydrogen; macrocycles; nanotubes