Bridging, non-bridging and free (O2–) oxygen in Na2O-SiO2 glasses: An X-ray Photoelectron Spectroscopic (XPS) and Nuclear Magnetic Resonance (NMR) study

Nesbitt, H.W.; Bancroft, G.M.; Henderson, Grant S.; Ho, R.; Dalby, Kim N.; Huang, Yu‐Fen; Yan, Z. Blossom

doi:10.1016/j.jnoncrysol.2010.09.031

Cited by 276 publications

(201 citation statements)

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“…It can be observed that the contribution of Ce +3 to the overall spectra followed the trend Ni-CeO 2 /G-Na > Ni/CeO 2 > Ni-CeO 2 /G. Finally, the Na 1s region for samples Ni-CeO 2 /G-Na and Ni/G-Na displayed one contribution at 1071.5-1071.6 eV, which is between the values reported for metallic Na and Na 2 O or NaOH [42] and, considering the results obtained for the O 1s and Ce 3d regions, it might be ascribed to sodium interacting with Ce and Ni forming Na-O-Ce and Na-O-Ni species.…”

Section: Characterizationsupporting

confidence: 54%

Promoter effect of sodium in graphene-supported Ni and Ni–CeO2 catalyst for the low-temperature WGS reaction

Dongil

Pastor‐Pérez

Sepúlveda-Escribano

et al. 2015

Applied Catalysis A: General

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Graphical abstract Highlights-Graphene-supported Ni and Ni-CeO 2 catalysts have been studied.-Metal dispersion depends on the presence of ceria and on the precipitating agent, NaOH or urea.-The graphene support strongly interacts with the ceria promoter.-The presence of sodium increases the catalytic activity, mainly in the presence of ceria. AbstractThe low temperature water-gas shift (WGS) reaction has been studied over NiCeO 2 /Graphene and Ni/Graphene. The catalysts were prepared with 5 wt% Ni and 20 wt% CeO 2 loadings, by deposition-precipitation employing sodium hydroxide and urea as precipitating agents. The materials were characterized by TEM, powder X-ray diffraction, Raman spectroscopy, H 2 -temperature-programmed reduction and X-ray photoelectron spectroscopy (XPS). The characterization and the reaction results indicated that the interaction between the active species and the support is higher than with activated carbon, and this hinders the reducibility of ceria and thus the catalytic performance. On the other hand, the presence of residual sodium in samples prepared by precipitation with NaOH facilitated the reduction of ceria. The catalytic activity was highly improved in the presence of sodium, what can be explained on the basis of an associative reaction mechanism which is favored over Ni-O-Na entities.

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Section: Characterizationsupporting

confidence: 54%

Promoter effect of sodium in graphene-supported Ni and Ni–CeO2 catalyst for the low-temperature WGS reaction

Dongil

Pastor‐Pérez

Sepúlveda-Escribano

et al. 2015

Applied Catalysis A: General

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“…Because XPS data for Ir are scarce in the literature, and the alkalifused Ir compounds do not form stable crystal structures, there is considerable disagreement in the literature, and the peaks for binding energies are not symmetrical. [20][21][22][23][24] Based on the results of previous research studies, 25,26) the binding energy of 64.17 eV can be assigned to IrO 2 with nano-scale features. The appearance of the peak at 68.45 eV may be a result of final-state screening, such as a conduction band interaction during the photoemission process.…”

Section: Resultsmentioning

confidence: 99%

Chemical Dissolution of Iridium Powder Using Alkali Fusion Followed by High-Temperature Leaching

Lee

Kim

2011

Mater. Trans.

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The dissolution of iridium has been investigated with an alkali fusion treatment with Na 2 O 2 followed by leaching in HCl solution. Alkali fusion with Na 2 O 2 allows Ir to be easily oxidized to IrO 2 , which is transformed to a high oxidation state through the binding of Na-Ir-O at 600 C for 4 h. From the fused mixture, with molar ratio of 1 : 2:0 (Ir : Na 2 O 2 ), Ir can be leached completely at 130 C using an HCl solution with a concentration above 3 M. Moreover, the leaching with 3 M HCl at 130 C can dissolve Ir from the mixture that was fused at 600 C, regardless of molar ratio of Na 2 O 2 . Ir can also be completely dissolved at 70 C or less when the fused mixture has a 1 : 2:0 ratio.

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“…• The value of (3, 2) 3 8 which corresponds to the microstate S 3 8 (or Q 3 224 ) would be 2 because there are two 3 → 2 connections.…”

Section: B Statistical Treatmentmentioning

confidence: 99%

“…Though, at lower concentrations of R 2 O (orŔO), the amount of FOs in the composition is negligible. 2,3 Providentially, these compositions are of interest to the glass science because of their glass forming ability. The BOs and NBOs are present on the corners of silicate tetrahedra where the BOs act as connectors between two tetrahedra, while the NBOs terminate the connectivity of a given tetrahedron.…”

Section: Introductionmentioning

confidence: 99%

Statistics of silicate units in binary glasses

Gaddam

Montagne

2016

The Journal of Chemical Physics

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In this paper, we derive a new model to determine the distribution of silicate units in binary glasses (or liquids). The model is based on statistical mechanics and assumes grand canonical ensemble of silicate units which exchange energy and network modifiers from the reservoir. This model complements experimental techniques, which measure short range order in glasses such as nuclear magnetic resonance (NMR) spectroscopy. The model has potential in calculating the amounts of liquid-liquid phase segregation and crystal nucleation, and it can be easily extended to more complicated compositions. The structural relaxation of the glass as probed by NMR spectroscopy is also reported, where the model could find its usefulness. Published by AIP Publishing. [http://dx

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Bridging, non-bridging and free (O2–) oxygen in Na2O-SiO2 glasses: An X-ray Photoelectron Spectroscopic (XPS) and Nuclear Magnetic Resonance (NMR) study

Cited by 276 publications

References 50 publications

Promoter effect of sodium in graphene-supported Ni and Ni–CeO2 catalyst for the low-temperature WGS reaction

Promoter effect of sodium in graphene-supported Ni and Ni–CeO2 catalyst for the low-temperature WGS reaction

Chemical Dissolution of Iridium Powder Using Alkali Fusion Followed by High-Temperature Leaching

Statistics of silicate units in binary glasses

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