Functionalization of LiFePO4/C by Spontaneous Reduction of In-situ Generated Bromobenzene Diazonium Ions in Organic Media

2015 ◽  
Vol 1773 ◽  
pp. 21-26
Author(s):  
Nicolas Delaporte ◽  
Karim Zaghib ◽  
Daniel Bélanger
Keyword(s):  
Photoelectron Spectroscopy ◽  
Organic Media ◽  
Agglomerate Size ◽  
X Ray ◽  
Organic Species ◽  
Spontaneous Reduction ◽  
Diazonium Ions ◽  
Carbon Coated

ABSTRACTBromophenyl moieties were attached to the carbon-coated LiFePO4 (LiFePO4/C) surface by spontaneous reduction of in-situ generated 4-bromobenzene diazonium ions in organic media. The presence of the surface organic species on the grafted LiFePO4/C powders was confirmed by X-ray photoelectron spectroscopy. Thermogravimetric analyses revealed a low loading (lower than 1 wt. %) of grafted molecules. The electrochemical characterization of the LiFePO4/C cathodes showed that a low loading of bromophenyl groups at the LiFePO4/C surface can enhance the rate of Li+ extraction, presumably due to the decrease of the LiFePO4/C agglomerate size and an increase of the wettability of the electrode. On the other hand, poor performances were obtained using the grafted cathode material with the highest loading of bromophenyl moieties.

scholarly journals Characterization of Ti/SnO2 Interface by X-ray Photoelectron Spectroscopy

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 202
Author(s):  
Miranda Martinez ◽  
Anil R. Chourasia
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Chemical Interaction ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Increasing Trend ◽  
Substrate Temperatures ◽  
Beam Technique

The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. The relative percentages of the constituents at the interface have been estimated by curve fitting the spectral data with the corresponding elemental and the oxide spectra. In the 200 °C samples, thermal diffusion of the titanium overlayer was observed. This resulted in the complete oxidation of the titanium overlayer to TiO2 upto a thickness of 0.9 nm of the overlayer. Elemental titanium resulting from the unreacted overlayer was observed to be more in the room temperature samples. The room temperature samples showed variation around 20% for the Ti-suboxide while an increasing trend was observed in the 200 °C samples.

In situ formation of bromobenzene diazonium ions and their spontaneous reaction with carbon-coated LiFePO4 in organic media

2016 ◽  
Vol 40 (7) ◽  
pp. 6135-6140 ◽  
Author(s):  
Nicolas Delaporte ◽  
Karim Zaghib ◽  
Daniel Bélanger
Keyword(s):  
Organic Media ◽  
Diazonium Ions ◽  
Carbon Coated ◽  
In Situ Formation ◽  
Spontaneous Reaction

In this study, the diazotization of bromoaniline in the presence of carbon-coated LiFePO4 and the grafting of bromobenzene moieties are investigated.

scholarly journals Hydrogenative Cyclization of Levulinic Acid to γ-Valerolactone with Methanol and Ni-Fe Bimetallic Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1096
Author(s):  
Ligang Luo ◽  
Xiao Han ◽  
Qin Zeng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Levulinic Acid ◽  
Hydrogen Donor ◽  
Effect Of Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Temperature Programmed

A series of Ni-Fe/SBA-15 catalysts was prepared and tested for the catalytic hydrogenation of levulinic acid to γ-valerolactone, adopting methanol as the only hydrogen donor, and investigating the synergism between Fe and Ni, both supported on SBA-15, towards this reaction. The characterization of the synthesized catalysts was carried out by XRD (X-ray powder diffraction), TEM (transmission electron microscopy), H2-TPD (hydrogen temperature-programmed desorption), XPS (X-ray photoelectron spectroscopy), and in situ FT-IR (Fourier transform–infrared spectroscopy) techniques. H2-TPD and XPS results have shown that electron transfer occurs from Fe to Ni, which is helpful both for the activation of the C=O bond and for the dissociative activation of H2 molecules, also in agreement with the results of the in situ FT-IR spectroscopy. The effect of temperature and reaction time on γ-valerolactone production was also investigated, identifying the best reaction conditions at 200 °C and 180 min, allowing for the complete conversion of levulinic acid and the complete selectivity to γ-valerolactone. Moreover, methanol was identified as an efficient hydrogen donor, if used in combination with the Ni-Fe/SBA-15 catalyst. The obtained results are promising, especially if compared with those obtained with the traditional and more expensive molecular hydrogen and noble-based catalysts.

Synthesis and characterization of organic–inorganic poly(3,4-ethylenedioxythiophene)/MoS2 nanocomposite via in situ oxidative polymerization

2006 ◽  
Vol 21 (1) ◽  
pp. 112-118 ◽  
Author(s):  
A. Vadivel Murugan ◽  
Mathieu Quintin ◽  
Marie-Helene Delville ◽  
Guy Campet ◽  
Annamraju Kasi Viswanath ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxidative Polymerization ◽  
X Ray Diffraction ◽  
Rechargeable Lithium Batteries ◽  
X Ray ◽  
Transmission Electron ◽  
Basal Distance ◽  
New Type

Here we demonstrate the synthesis of a new type of layered poly(3,4-ethylenedioxy- thiophene) (PEDOT)/MoS2 nanocomposite via flocculation of delaminated MoS2 with subsequent in situ oxidative polymerization of 3,4-ethylenedioxythiophene. The resulting nanocomposite was characterized by Fourier transform infrared spectroscopy, powder x-ray diffraction, x-ray photoelectron spectroscopy, thermal analysis, transmission electron microscopy, and four-probe electrical conductivity measurements with respect to temperature. X-ray diffraction results indicated that the exfoliated MoS2 and PEDOT are restacked to produce a novel nanoscale composite material containing alternate nanoribbons of PEDOT in between MoS2 with a basal distance of ∼1.38 nm. The nanocomposite, which could be used as a cathode material for small power rechargeable lithium batteries, has also been demonstrated by the electrochemical insertion of lithium into the PEDOT/MoS2 nanocomposite, where a significant enhancement in the discharge capacity is observed, compared to that of respective pristine molybdenum disulfide.

In situ characterization of the nitridation of AIII–BV semiconductor surfaces by means of X-ray photoelectron spectroscopy

2001 ◽  
Vol 179 (1-4) ◽  
pp. 196-202 ◽  
Author(s):  
J.-D Hecht ◽  
F Frost ◽  
T Chassé ◽  
D Hirsch ◽  
H Neumann ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Semiconductor Surfaces ◽  
In Situ Characterization ◽  
X Ray

New approach in the monitoring and characterization of titanium nitride thin films

1999 ◽  
Vol 14 (2) ◽  
pp. 436-441 ◽  
Author(s):  
S. Logothetidis ◽  
E. I. Meletis ◽  
G. Kourouklis
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Ex Situ ◽  
New Approach ◽  
X Ray ◽  
Plasma Energy

In situ and ex situ spectroscopic ellipsometry (SE), Raman spectroscopy (RS), x-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) have been used to study the stoichiometry and characterize TiNx thin films deposited by magnetron sputtering at various stoichiometries. In situ SE can provide parameters, such as the plasma energy, that can be utilized for monitoring of the film stoichiometry. Besides plasma energy, optical phonon position in RS was also found to be a sensitive probe of TiNx stoichiometry as detected by RS, XPS, and ex situ SE. Under these conditions, AES faces difficulties for reliable film characterization, and the complementary use of other techniques is required for determining the exact film stoichiometry.

In situ X-ray photoelectron and Auger electron spectroscopic characterization of reaction mechanisms during Li-ion cycling

2016 ◽  
Vol 52 (90) ◽  
pp. 13257-13260 ◽  
Author(s):  
Ching-Yen Tang ◽  
Richard T. Haasch ◽  
Shen J. Dillon
Keyword(s):  
Photoelectron Spectroscopy ◽  
Reaction Mechanisms ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Spectroscopic Characterization ◽  
X Ray ◽  
Li Ion ◽  
Novel Design

We demonstrate a novel design for in situ X-ray photoelectron spectroscopy and in situ Auger electron spectroscopy, and we applied this technique to characterize the evolution of bonding and chemistry during cycling of nanoparticle electrodes.

scholarly journals Preparation and Characterization of Hydrophobically Grafted Starches by In Situ Solid Phase Polymerization

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 72 ◽  
Author(s):  
Yingfeng Zuo ◽  
Xiaoyu He ◽  
Ping Li ◽  
Wenhao Li ◽  
Yiqiang Wu
Keyword(s):  
Molecular Weight ◽  
Photoelectron Spectroscopy ◽  
Solid Phase ◽  
Graft Polymer ◽  
X Ray ◽  
Grafting Reaction ◽  
Grafting Ratio ◽  
Ft Ir

Three kinds of hydrophobic groups grafted starches of maleic anhydride grafted starch (MAH-g-starch), lactic acid grafted starch (LA-g-starch), and methyl acrylate grafted starch (MA-g-starch) were prepared by in situ solid phase polymerization. The results of Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) confirmed successful grafting. The grafting ratios of MAH-g-starch, LA-g-starch, and MA-g-starch were 6.50%, 12.45%, and 0.57%, respectively. Influenced by the grafting ratio, LA-g-starch had the best relative hydrophobicity and the largest molecular weight, and those for MA-g-starch were the worst. The surfaces of grafted starches were covered with graft polymer, with obvious surface roughness and bond degree of MAH-g-starch and LA-g-starch. The crystalline structure of grafted starches showed some damage, with LA-g-starch exhibiting the greatest decrease in crystallinity, and less of a change for MA-g-starch. Overall, the grafting reaction improved thermoplasticity, with LA-g-starch the most improved, followed by MAH-g-starch, and then MA-g-starch.

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