Bonding in hard and elastic amorphous carbon nitride films investigated using<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>15</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">N</mml:mi><mml:mo>,</mml:mo></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>13</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">C

Gammon, W. J.; Hoatson, Gina L.; Holloway, Brian C.; Vold, Robert L.; Reilly, A. C.

doi:10.1103/physrevb.68.195401

Cited by 37 publications

(10 citation statements)

References 25 publications

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“…This signal could be a superposition of several possible structures. Comparing the values in the literature with our results, the signal at –310 ppm can be assigned as nitrogen in a h ‐BN unit14 and the signal near –290 ppm as nitrogen in a pyrrole like nitrogen structure 15. Graphitic or amorphous C 3 N 4 also can be one of the possible structures.…”

Section: Resultssupporting

confidence: 80%

Solid‐State NMR Investigations on the Amorphous Network of Precursor‐Derived Si₂B₂N₅C₄ Ceramics

Sehlleier

Verhoeven

Jansen

2012

Zeitschrift anorg allge chemie

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Employing a multitude of modern solid state NMR techniques including 13 C{ 15 N}REDOR NMR, 1 H-13 C CP NMR, 11 B MQMAS NMR spectroscopic experiments, the structural organization of Si 2 B 2 N 5 C 4 ceramic has been studied. The experiments were executed on double isotope enriched ( 13 C, 15 N) and natural isotope abundance Si 2 B 2 N 5 C 4 ceramics. The materials were synthesized by aminolysis and subsequent pyrolysis of intermediate pre-ceramic polymers that were obtained from the single source precursor TSDE, 1-(tri-

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Section: Resultssupporting

confidence: 80%

Solid‐State NMR Investigations on the Amorphous Network of Precursor‐Derived Si₂B₂N₅C₄ Ceramics

Sehlleier

Verhoeven

Jansen

2012

Zeitschrift anorg allge chemie

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“…However, the alternative view, founded on the experimental data collected from polymerised heptazine (melon), attributes it to the protons of hydrogen-bonded water molecules [53,55]. The decrease of the intensity of this maximum under in-situ heat treatment at 150 °C in NMR apparatus is in accord with the above hypothesis [56]. Although adsorbed water is not a part of the structural PCN unit, the type of its interaction with PCN gives information about the state of the surface species in the photocatalysts.…”

Section: Figure 4 Tablementioning

confidence: 82%

Selective photocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxaldehyde by polymeric carbon nitride-hydrogen peroxide adduct

Ilkaeva

Krivtsov

García‐López

et al. 2018

Journal of Catalysis

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Polymeric carbon nitride-hydrogen peroxide adduct (PCN-H2O2) has been prepared, thoroughly characterised and its application for selective photocatalytic conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxaldehyde (FDC) in aqueous suspension has been studied. The PCN-H2O2 adduct is stable in aqueous suspension under UV and solar irradiation up to 100 °C. It is also stable up to 200 °C if heated in air, while at temperatures close to 300 °C its decomposition takes place. Based on the obtained characterisation data it has been proposed that H2O2 attaches to the non-polymerised carbon nitride species and to the heptazine nitrogen atoms, thus producing strong hydrogen bonding within the PCN-H2O2 adduct. The blockage of the surface amino-groups in PCN-H2O2 by H2O2 hinders the interaction of HMF with these sites, which are responsible for unselective substrate conversion. PCN-H2O2 possesses a superior selectivity in natural solar light assisted oxidation of HMF to FDC reaching 80% with respect to its thermally etched PCN counterpart, which gives rise to a 40-50% selectivity. We believe that the exceptional performance of the applied photocatalyst in the selective photocatalytic conversion of HMF to a high added value FDC in a green solvent under natural illumination makes a significant contribution to the development of environmentally friendly technologies for biomass valorisation.

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“…When carbon surface bears hydroxyl groups, which generate water by thermal decomposition, as seen by water TPD for NH42 and NP75-873 ( Fig. 1), the XPS peak P3 could also be assigned to quaternary nitrogen resulting from weak pyridine protonation by adjacent or nearby located hydroxyl groups forming hydrogen bridge with the pyridinic nitrogen [31][32][33][34].…”

Section: Xps and Xanesmentioning

confidence: 99%

Nitrogen in aramid-based activated carbon fibers by TPD, XPS and XANES

Boudou

Parent

Suárez-Garcı́a

et al. 2006

Carbon

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Activated carbon fibers were prepared from Nomex@ [poly(m-phenylene isophthalamide)] by either H3PO4 activation, H3PO4-CO2 activation, or simply CO2 or steam activation. These treatments converted amide groups from the polymer precursor into complex and heterogeneously distributed nitrogen functionalities. TPD, XPS and XANES were used to study the effects of these treatments on the local bonding environment around nitrogen in the resulting carbons. These analytical techniques showed that nitrogen atoms are present in the 6-membered rings located at the edges of condensed polyaromatic systems as pyridine-like sp 2 nitrogen (N1 or N2) or in the interior, where nitrogen replaces one carbon atom and is bonded to three carbon neighbors (N3). The occurrence of a species (N2) hypothetically related to a pyridinic cycle bearing oxygen substituents or intracyclic oxygen atoms could be correlated with the degree of oxidation of the carbon surface. Assuming that a relative N3 increase is indicative of aromatization and that the reverse, correlated with a N2 increase, is indicative of surface oxidative denitrogenation, the ratio between these nitrogen species revealed that aromatization and oxidative denitrogenation processes occur sequentially or simultaneously to different extents according to the type of carbon activation and to the burn-off degree. Physical activation involves thermal aromatization reactions during the carbonization stage and the subsequent isothermal activation one. In this second activation stage, co-occurring thermal oxidation reactions lead to a less intense denitrogenation during CO2 activation than during steam activation. H3PO4 activation induces the largest nitrogen retention in the final product in a double process of aromatization and ''auto-activation'' producing a moderate oxidative attack of nitrogen. However, an increase of the H3PO4 ratio fostered the oxidation of the carbon surface and consequently enhanced nitrogen gasification during the subsequent activation.

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Bonding in hard and elastic amorphous carbon nitride films investigated using15N,13C

Cited by 37 publications

References 25 publications

Solid‐State NMR Investigations on the Amorphous Network of Precursor‐Derived Si₂B₂N₅C₄ Ceramics

Solid‐State NMR Investigations on the Amorphous Network of Precursor‐Derived Si₂B₂N₅C₄ Ceramics

Selective photocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxaldehyde by polymeric carbon nitride-hydrogen peroxide adduct

Nitrogen in aramid-based activated carbon fibers by TPD, XPS and XANES

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Bonding in hard and elastic amorphous carbon nitride films investigated using15N,13C

Cited by 37 publications

References 25 publications

Solid‐State NMR Investigations on the Amorphous Network of Precursor‐Derived Si2B2N5C4 Ceramics

Solid‐State NMR Investigations on the Amorphous Network of Precursor‐Derived Si2B2N5C4 Ceramics

Selective photocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxaldehyde by polymeric carbon nitride-hydrogen peroxide adduct

Nitrogen in aramid-based activated carbon fibers by TPD, XPS and XANES

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Solid‐State NMR Investigations on the Amorphous Network of Precursor‐Derived Si₂B₂N₅C₄ Ceramics

Solid‐State NMR Investigations on the Amorphous Network of Precursor‐Derived Si₂B₂N₅C₄ Ceramics