XPS/XAES study of carbon fibres during thermal annealing under UHV conditions

Desimoni, E.; Casella, Innocenzo G.; Salvi, Anna Maria

doi:10.1016/0008-6223(92)90170-2

Cited by 132 publications

(62 citation statements)

References 29 publications

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“…In the case of oxygen, for the GO-B sample, the peak at 533.0 eV is related to C-O in epoxy, phenol or carboxylic groups and the one at 535.0 eV -to oxygen atoms in water or chemisorbed oxygen species (COOH). 36,37 In the case of GO-H sample, the peak at 530.8 eV is assigned to oxygen atoms from C=O in carboxyl or carbonyl groups. The second peak at 532.2 eV is related to C-O in epoxy, phenol or carboxylic groups, and the third one at 533.2 eV-to oxygen atoms in water or chemisorbed oxygen species.…”

Section: Resultsmentioning

confidence: 99%

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

2009

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Graphical content entryThe mechanism of ammonia adsorption on graphite oxide (GO) is strongly related to the GO preparation and chemical features, especially to the sulfur-containing groups present on its surface. SummaryGraphite oxide (GO) was synthesized using two different methods: one with sulfuric acid as part of the oxidizing mixture (Hummers-Offeman method), and another one without the sulfurcontaining compound involved in the oxidation process (Brodie method). They were both tested for ammonia adsorption in dynamic conditions, at ambient temperature, and characterized before 2 and after exposure to ammonia by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, potentiometric titration, energy-dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS) and elemental analysis. Analyses of the initial materials showed that besides epoxy, hydroxyl and carboxylic groups, a significant amount of sulfur is incorporated as sulfonic group for GO prepared by the Hummers-Offeman method. The process of ammonia adsorption seems to be strongly related to the type of GO. For GO prepared by the Brodie method, ammonia is mainly retained via intercalation in the interlayer space of GO and by reaction with the carboxylic groups present at the edges of the graphene layers. On the contrary, when GO prepared by the Hummers method is used, ways of retention are different: not only does the intercalation of ammonia is observed but also its reaction with the epoxy, carboxylic and sulfonic groups present. In particular, during the ammonia adsorption process, sulfonic groups are converted to sulfates in presence of superoxide anions O 2 -* . These sulfates can then react with ammonia to form ammonium sulfates. For both GOs, an incorporation of a significant part of the ammonia adsorbed as amines in their structure is observed as a result of reactive adsorption.

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Section: Resultsmentioning

confidence: 99%

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

2009

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“…High resolution scans were performed on the C1s and O1s to identify the carbon and oxygen species present, the assignment and molar abundance of which are summarised in Table 7. A complicated envelope was produced for the C1s, and was deconvoluted into six components commonly assigned in the analysis of carbon materials to: (a) carbide, (b) graphitic carbon, (c) aliphatics, (d) hydroxyls/ethers, (d) carbonyls, and (f) carboxyls/esters [59][60][61][62][63][64]. The O1s spectra is less complicated, with only 2 components fitted (Table 7), assigned to: (a) C=O in carbonyl and carboxyl groups, and (b) singly bonded oxygen assigned to -O-or C-OH in hydroxyl and carboxylic functional groups [60,64].…”

Section: Chemical and Textural Propertiesmentioning

confidence: 99%

Influence of oxidation upon the CO2 capture performance of a phenolic-resin-derived carbon

Plaza¹,

Thurecht²,

Pevida³

et al. 2013

Fuel Processing Technology

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The effect of oxidation upon the CO 2 capture performance has been studied taking a phenolic resin carbon as the base material. Oxygen surface groups were introduced through liquid and gas phase oxidation treatments, using ammonium persulfate, nitric acid and air, respectively.The surface chemistry of the final carbon is strongly affected by the type of oxidation treatment: liquid phase oxidation introduces a greater amount of oxygen, mostly as carboxylic groups; these are absent in the gas phase oxidised sample that contains mainly ether and carbonyl functionalities. The porous texture of the samples is also affected by the oxidation treatment: through liquid phase oxidation the pore volume is somewhat reduced, while this is slightly developed by air treatment at 693 K. Despite the reduction in the porous volume and the acidic surface, liquid-phase oxidised samples present greater CO 2 adsorption capacity than the starting carbon due to Lewis acid-base interactions with the CO 2 molecule.Moreover: oxidised samples are easily regenerated, and observed heats of adsorption are † Corresponding Author: Tel : +34 985 119090; E-mail address: frubiera@incar.csic.es. (F. Rubiera) 2 typical from physisorption processes, which will facilitate the adsorbent regeneration in cyclic adsorption processes. Oxidation is therefore proposed as a plausible modification technique for developing easy-to-regenerate carbon adsorbents with enhanced CO 2 capture performance.

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“…CasaXPS software was used for data treatment using a Shirley background correction. The models used to decompose the C1s, S2p and P2p peaks were those proposed by Desimoni et al [36], Terzyk [37] and Puziy et al [38], respectively. The O1s region was decomposed, as suggested by Zhou et al [39]; in addition, two components corresponding to P−O and P═O contributions were used.…”

Section: Xpsmentioning

confidence: 99%

Role of phosphorus in carbon matrix in desulfurization of diesel fuel using adsorption process

Seredych

Wu²,

Brender

et al. 2012

Fuel

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Adsorptive removal of dibenzothiophene (DBT) and 4, from model diesel fuel with 20 ppmw total concentration of sulfur was investigated on polymerderived carbons with incorporated heteroatoms of oxygen, sulfur and phosphorus. The materials before and after exposure to model diesel fuel were characterized using adsorption of nitrogen, thermal analysis, potentiometric titration, XPS and elemental analysis. The selectivities for DBT and DMDBT adsorption were calculated with reference to naphthalene. The results indicated that the presence of phosphorus, especially in the form of pyrophosphates and P 2 O 5 , increases the capacity and selectivity for removal of dibenzothiophenes. It also affects the adsorption mechanism. Phosphorus suppresses oxidation reactions of DBT and DMDBT. Owing to a possible location of bulky phosphorus groups in pore with sizes between 10-30 Å thiophenic molecules are strongly adsorbed there via dispersive forces. Acidic environment also enhances adsorption via acid-base interactions. Physical adsorption mechanism and stability of surface make these carbons attractive candidates for thermal regeneration.

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XPS/XAES study of carbon fibres during thermal annealing under UHV conditions

Cited by 132 publications

References 29 publications

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

Influence of oxidation upon the CO2 capture performance of a phenolic-resin-derived carbon

Role of phosphorus in carbon matrix in desulfurization of diesel fuel using adsorption process

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