Chemical transformation during the carbonisation in air and the pyrolysis under argon of a vinylpyridine–divinylbenzene copolymer by X-ray photoelectron spectroscopy

Lahaye, J.; Nanse, G.; Fioux, Ph; Bagreev, and Andrei; Broshnik, A. P.; Strelko, V. V.

doi:10.1016/s0169-4332(99)00108-7

Cited by 48 publications

(23 citation statements)

References 19 publications

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“…Pyridinic nitrogen atoms are bonded only to two C atoms in an aromatic π-electron system. The observed 113.8 eV offset Δ|N 1s -C 1s| is in agreement with reported values for pyridinic model compounds, such as 3,5,11,13-tetraazacycl-[3,3,3]-azine or pyrolysates of acridine, 9-aminoacridine, 9-cyanoanthracene, 2-aminoanthracene, poly(vinylpyrrolidone), and phenazine (reviewed by Lahaye et al, 1999). Temperature-programmed pyrolysis of anthracites demonstrated the absence of NH 3 in closed micropores, although traces of N 2 were found in meta-anthracite (Boudou and Espitalié, 1995).…”

Section: Sub-peak N-6: Contribution From Pyridinic Nitrogensupporting

confidence: 90%

Organic nitrogen chemistry during low-grade metamorphism

Boudou

Schimmelmann

Ader

et al. 2008

Geochimica et Cosmochimica Acta

136

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-Most of the organic nitrogen (N org ) on Earth is disseminated in crustal sediments and rocks in the form of fossil nitrogen-containing organic matter. The chemical speciation of fossil N org within the overall molecular structure of organic matter changes with time and heating during burial. Progressive thermal evolution of organic matter involves phases of enhanced elimination of N org and ultimately produces graphite containing only traces of nitrogen. Long-term chemical and thermal instability makes the chemical speciation of N org a valuable tracer to constrain the history of sub-surface metamorphism and to shed light on the subsurface biogeochemical nitrogen cycle and its participating organic and inorganic nitrogen pools. This study documents the evolutionary path of N org speciation, transformation and elimination before and during metamorphism and advocates the use of XRay Photoelectron Spectroscopy (XPS) to monitor changes in N org speciation as a diagnostic tool for organic metamorphism. Our multidisciplinary evidence from XPS, stable isotopes, traditional quantitative coal analyses, and other analytical approaches shows that at the metamorphic onset N org is dominantly present as pyrrolic and pyridinic nitrogen. The relative abundance of nitrogen substituting for carbon in condensed, partially aromatic systems (where N is covalently bonded to three C atoms) increases exponentially with increasing metamorphic grade, at the expense of pyridinic and pyrrolic nitrogen. At the same time, much N org is eliminated without significant nitrogen isotope fractionation. The apparent absence of Rayleigh-type nitrogen isotopic fractionation suggests that direct thermal loss of nitrogen from an organic matrix does not serve as a major pathway for N org elimination. Instead, we propose that hot H, O-containing fluids or some of their components gradually penetrate into the carbonaceous matrix and eliminate N org along a progressing reaction front, without causing nitrogen isotope fractionation in the residual N org in the unreacted core of the carbonaceous matrix. Before the reaction front can reach the core, an increasing part of core N org chemically stabilizes in the form of nitrogen atoms substituting for carbon in condensed, partially aromatic systems forming graphite-like structural domains with delocalized π-electron systems (nitrogen atoms substituting for "graphitic" carbon in natural metamorphic organic matter). Thus, this nitrogen species with a conservative isotopic composition is the dominant form of residual nitrogen at higher metamorphic grade.

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Section: Sub-peak N-6: Contribution From Pyridinic Nitrogensupporting

confidence: 90%

Organic nitrogen chemistry during low-grade metamorphism

Boudou

Schimmelmann

Ader

et al. 2008

Geochimica et Cosmochimica Acta

136

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“…Caution should be taken regarding the assignment of XPS peaks to chemical groups since the low abundance of N increases the uncertainty of the multicomponent curve-fitting peak and, non-conductive samples (EAT, H-AT and H-EAT) could lead to local charging effect with shifted binding energy to higher values. Moreover, the assignment is complicated by the location of N within the polyaromatic network and the degree of condensation of the graphene layer (Lahaye et al, 1999). For instance, N in pyridinic groups has its core level binding energy that lie from 398.3 eV for conducting samples (e.g.…”

Section: Xps Analysismentioning

confidence: 99%

High surface – Highly N-doped carbons from hydrothermally treated tannin

Braghiroli

Fierro

Izquierdo

et al. 2015

Industrial Crops and Products

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a b s t r a c tNitrogen-doped carbon materials (NCMs) were obtained by amination of tannin by hydrothermal carbonisation (HTC). NCMs presented different morphologies depending on the amination method: (i) powders by HTC of tannin in a concentrated aqueous ammonia solution; (ii) gels without using any crosslinker by HTC in distilled water of tannin first dissolved in concentrated ammonia and then evaporated. Whatever the method, (i) or (ii), HTC was carried out at different temperatures: 180, 190, 200, 210 or 220 • C, with further pyrolysis at 900 • C under nitrogen. The morphology and chemical composition of the resultant materials were discussed. We compared our results with those reported in the open literature and we concluded that HTC of tannin in a concentrated aqueous ammonia solution allowed obtaining outstanding materials because they have both surface areas, higher than 500 m 2 g −1 , and high N content, around 8 wt.%.

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“…As an illustration, the XPS spectra of the V15NS and V15NN samples are shown in figure 4. The N1S signal is split in five peaks [28,30,31].…”

Section: Nitrogen Speciationmentioning

confidence: 99%