Evolution of nitrogen functionalities in carbonaceous materials during pyrolysis

Dynamic surface rearrangement and thermal stability of nitrogen functional groups on carbon nanotubes

“…Scheme2 summarizes the modification of nitrogen functionalities during thermal treatment. Similar results have been reported earlier [13] for NH 3 treatment on activated carbon.…”

“…The N3 species is the most thermal stable species, it is generally referred in literature as quaternary nitrogen but the exact nature of this functionality is still poorly established. Early it was reported that an hypotetical structure of this functionality could be as reported in scheme2 [13]. Thus a surface reassembling of graphite cluster during heating occurs, leading to aromatization with introduction of a small amount of N in the graphitic structure.…”

“…The pyridone functionality is the tautomeric form of lactame functionality. The third region (labelled as N3, at 401-403eV) is referred to the quaternary nitrogen, including protonated pyridine or the "graphitic" nitrogen when the nitrogen atom is incorporated in the graphene layer replacing carbon atom [13]. Furthermore, a peak labelled as N4 with a binding energy shift of +5eV compared to pyridine is assigned to pyridine oxide.…”

From spent Mg/Al layered double hydroxide to porous carbon materials

“…Namely, the relative content of oxygen-containing hydrophilic groups decreased, which indicated a better hydrophobicity for Carbon-800 than Carbon-600. Deconvolution of the N 1 s spectra mainly yield three peaks, which could be identified as C N C (sp 2 hybridization form) (∼398.3 eV) [37], C N C (other hybridization forms) (∼400.1 eV) [35,38], and C N + H C (∼401.4 eV) [35,38]. The binding forms of N atom presented mainly as C N C forms (sp 2 and other hybridization forms), and showed no clear change in the relative content among all the N-containing groups with the increase of carbonization temperature from 600 to 800 • C (Table S1).…”

Activity of Nitrogen Containing Carbon Nanotubes in Base Catalyzed Knoevenagel Condensation

“…The basic character of the NCNT originates from the presence of pyridinic like nitrogen (N P ), located at the edges of the graphene layers [26,27]. Other nitrogen types present are quaternary N (N Q ), pyrrolic N (N PYR ) and oxidized pyridinic N (N OX ) [28][29][30] however their role in base-catalysis is expected to be limited.…”