XPS investigation of the reaction of carbon with NO, O2, N2 and H2O plasmas

Dou, S. (2016). Improved cycling stability of lithium-sulphur batteries by enhancing the retention of active material with a sandwiched hydrothermally treated graphite film. RSC Advances, 6 (41), 34131-34136. Improved cycling stability of lithium-sulphur batteries by enhancing the retention of active material with a sandwiched hydrothermally treated graphite film AbstractA new lithium-sulphur battery with a hydrothermally treated graphite film sandwiched between the separator and the sulphur cathode shows increased capacity, enhanced cycling stability and improved coulombic efficiency. After 50 cycles, a high capacity of 631 mA h g-1 is maintained, compared to 203 mA h g-1 for the Li-S battery with conventional configuration. Moreover, the coulombic efficiency is increased to near 100% from around 94%. This improved electrochemical performance could be attributed to the new cell configuration, because the graphite film greatly retains the active material by alleviating the polysulphide shuttling problem and providing extra reaction sites for sulphur species. Moreover, the Coulombic efficiency is increased to near 100% from around 94%. This improved electrochemical performance could be attributed to the new cell configuration, for the graphite film greatly retains the active material by elliviating the polysulphide shuttling problem and providing extra reaction sites for sulphur species.

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“…and O-C sp 2 species, respectively 13 . These oxygen species might have been introduced into the graphite under the hydrothermal treatment.…”

Section: Resultsmentioning

confidence: 99%

Improved cycling stability of lithium–sulphur batteries by enhancing the retention of active material with a sandwiched hydrothermally treated graphite film

et al. 2016

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“…The C1s region was fitted by peaks for C-Nb (282.7-282.9 eV) and C-C (sp 2 284.4 eV, sp 3 285.3 eV) [3,21] bonds (always after sputter removal of adventitious hydrocarbons). The O1s region was fitted by peaks for O-Nb (530.2 eV), O-C (*531.7), and O=C (*533.2 eV), where the two latter fits could be used to verify the removal of adventitious hydrocarbons [22,23]. The Nb3d region was fitted by peaks for NbNb (202.6 ± 0.1 eV), Nb-O ( 207.4 eV), and Nb-C (204.1 ± 0.1 eV) bonds, including their spin-orbit splits (?2.72 eV, equal FWHM, area ratio 2:3) [24].…”

Section: Methodsmentioning

confidence: 99%

Passive films on nanocomposite carbide coatings for electrical contact applications

et al. 2017

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Nanocomposite transition metal carbide/amorphous carbon coatings (Me-C/a-C) deposited by magnetron sputtering have excellent electrical contact properties. The contact resistance can be as low as that of noble metal coatings, although it is known to vary by several orders of magnitude depending on the deposition conditions. We have investigated a nanocrystalline niobium carbide/ amorphous carbon (NbC x /a-C:H) model system aiming to clarify factors affecting the contact resistance for this group of contact materials. For the first time, the surface chemistry is systematically studied, by angle-resolved X-ray photoelectron spectroscopy, and in extension how it can explain the contact resistance. The coatings presented a mean oxide thickness of about 1 nm, which could be grown to 8 nm by annealing. Remarkably, the contact resistances covered four orders of magnitude and were found to be exponentially dependent on the mean oxide thickness. Moreover, there is an optimum in the amount of a-C:H phase where the contact resistance drops very significantly and it is thus important to not only consider the mean oxide thickness. To explain the results, a model relying on surface chemistry and contact mechanics is presented. The lowest contact resistance of a nanocomposite matched that of a gold coating at 1 N load (vs. gold), and such performance has previously not been demonstrated for similar nanocomposite materials, highlighting their useful properties for electrical contact applications.

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“…We have also shown that perovskite catalysts are very efficient for the oxidation of CO at low temperatures in a plasma-catalyst device [17] and [18]. Although the reaction mechanism of carbon monoxide over perovskites has been the subject of numerous studies during the last years, there are still many open questions requiring further considerations.…”

Section: Introductionmentioning

confidence: 99%

“…The material is collected on a porous frit of quartz located in the outlet of the heating system. Subsequently, the amorphous powders were annealed at 600 °C for 4 h, thus obtaining a crystalline La 0.5 Sr 0.5 CoO 3−d perovskite structure with rhombohedral symmetry as evidenced by X-ray diffraction (d represents the oxygen deficiency of the perovskite) [8] and [17]. This preparation method renders the formation of pseudospherical particles ranging between two microns and 45-60 nm nanocrystalline domains as determined from Scherrer calculations.…”

Section: Catalyst Preparation and Characterizationmentioning

confidence: 99%

Near-ambient X-ray photoemission spectroscopy and kinetic approach to the mechanism of carbon monoxide oxidation over lanthanum substituted cobaltites

Hueso

Martínez-Martínez

Caballero

et al. 2009

Catalysis Communications

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We have studied the oxidation of carbon monoxide over a lanthanum substituted perovskite (La 0.5 Sr 0.5 CoO 3−d ) catalyst prepared by spray pyrolysis. Under the assumption of a first-order kinetics mechanism for CO, it has been found that the activation energy barrier of the reaction changes from 80 to 40 kJ mol −1 at a threshold temperature of ca. 320 °C. In situ XPS nearambient pressure ( 0.2 torr) shows that the gas phase oxygen concentration over the sample decreases sharply at ca. 300 °C. These two observations suggest that the oxidation of CO undergoes a change of mechanism at temperatures higher than 300 °C.

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XPS investigation of the reaction of carbon with NO, O2, N2 and H2O plasmas

Cited by 238 publications

References 53 publications

Improved cycling stability of lithium–sulphur batteries by enhancing the retention of active material with a sandwiched hydrothermally treated graphite film

Improved cycling stability of lithium–sulphur batteries by enhancing the retention of active material with a sandwiched hydrothermally treated graphite film

Passive films on nanocomposite carbide coatings for electrical contact applications

Near-ambient X-ray photoemission spectroscopy and kinetic approach to the mechanism of carbon monoxide oxidation over lanthanum substituted cobaltites

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