Depth Profiling of the Chemical Composition of Free-Standing Carbon Dots Using X-ray Photoelectron Spectroscopy

Glycyrrhizae Radix et Rhizoma (GRR) is one of the commonly used traditional Chinese medicines in clinical practice, which has been applied to treat digestive system diseases for hundreds of years. GRR is preferred for anti-gastric ulcer, however, the main active compounds are still unknown. In this study, GRR was used as precursor to synthesize carbon dots (CDs) by a environment-friendly one-step pyrolysis process. GRR-CDs were characterized by using transmission electron microscopy, high-resolution TEM, fourier transform infrared, ultraviolet-visible and fluorescence spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and high-performance liquid chromatography. In addition, cellular toxicity of GRR-CDs was studied by using CCK-8 in RAW264.7 cells, and the anti-gastric ulcer activity was evaluated and confirmed using mice model of acute alcoholic gastric ulcer. The experiment confirmed that GRR-CDs were the spherical structure with a large number of active groups on the surface and their particle size ranged from 2 to 10 nm. GRR-CDs had no toxicity to RAW264.7 cells at concentration of 19.5 to 5000 μg/mL and could reduce the oxidative damage of gastric mucosa and tissues caused by alcohol, as demonstrated by restoring expression of malondialdehyde, superoxide dismutase and nitric oxide in serum and tissue of mice. The results indicated the explicit anti-ulcer activity of GRR-CDs, which provided a new insights for the research on effective material basis of GRR.

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Uniform Depth Profiling in X-ray Photoelectron Spectroscopy (Electron Spectroscopy for Chemical Analysis)

Applied Spectroscopy ◽

10.1366/000370278774331468 ◽

1978 ◽

Vol 32 (2) ◽

pp. 175-177 ◽

Cited By ~ 12

Author(s):

L. Bradley ◽

Y. M. Bosworth ◽

D. Briggs ◽

V. A. Gibson ◽

R. J. Oldman ◽

...

Keyword(s):

Chemical Analysis ◽

Auger Electron Spectroscopy ◽

Photoelectron Spectroscopy ◽

Electron Spectroscopy ◽

Auger Electron ◽

Depth Profiling ◽

Ion Source ◽

X Ray ◽

Nitride Oxide ◽

Silicon Device

The difficulties of nonuniform ion etching which hamper depth profiling by X-ray photoelectron spectroscopy (XPS) have been overcome by use of a mechanically scanned saddle-field ion source. The system and its calibration for uniformity are described, and its performance is illustrated by the depth profile of a Si3N4/SiO2/Si metal nitride oxide silicon device. This also allows the potential advantages of XPS profiling over Auger electron spectroscopy profiling to be discussed.

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The effect of cobalt on morphology, structure, and ORR activity of electrospun carbon fibre mats in aqueous alkaline environments

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.12.87 ◽

2021 ◽

Vol 12 ◽

pp. 1173-1186

Author(s):

Markus Gehring ◽

Tobias Kutsch ◽

Osmane Camara ◽

Alexandre Merlen ◽

Hermann Tempel ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Elevated Temperatures ◽

Current Collector ◽

Alkaline Media ◽

Emission Spectrometry ◽

Free Standing ◽

X Ray ◽

Turbostratic Carbon ◽

Current Densities

An innovative approach for the design of air electrodes for metal–air batteries are free-standing scaffolds made of electrospun polyacrylonitrile fibres. In this study, cobalt-decorated fibres are prepared, and the influence of carbonisation temperature on the resulting particle decoration, as well as on fibre structure and morphology is discussed. Scanning electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, elemental analysis, and inductively coupled plasma optical emission spectrometry are used for characterisation. The modified fibre system is compared to a benchmark system without cobalt additives. Cobalt is known to catalyse the formation of graphite in carbonaceous materials at elevated temperatures. As a result of cobalt migration in the material the resulting overall morphology is that of turbostratic carbon. Nitrogen removal and nitrogen-type distribution are enhanced by the cobalt additives. At lower carbonisation temperatures cobalt is distributed over the surface of the fibres, whereas at high carbonisation temperatures it forms particles with diameters up to 300 nm. Free-standing, current-collector-free electrodes assembled from carbonised cobalt-decorated fibre mats display promising performance for the oxygen reduction reaction in aqueous alkaline media. High current densities at an overpotential of 100 mV and low overpotentials at current densities of 333 μA·cm−2 were found for all electrodes made from cobalt-decorated fibre mats carbonised at temperatures between 800 and 1000 °C.

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CVD Boron Carbo-Nitride as Pore Sealant for Ultra Low-K Interlayer Dielectrics

MRS Proceedings ◽

10.1557/proc-863-b6.8 ◽

2005 ◽

Vol 863 ◽

Cited By ~ 1

Author(s):

P. Ryan Fitzpatrick ◽

Sri Satyanarayana ◽

Yangming Sun ◽

John M. White ◽

John G. Ekerdt

Keyword(s):

Photoelectron Spectroscopy ◽

Depth Profiling ◽

Chemical Vapor ◽

K Value ◽

X Ray ◽

Dimethylamine Borane ◽

The Stability ◽

Low K ◽

Secondary Ion ◽

Sims Depth Profiling

AbstractBlanket porous methyl silsesquioxane (pMSQ) films on a Si substrate were studied with the intent to seal the pores and prevent penetration of a metallic precursor during barrier deposition. The blanket pMSQ films studied were approximately 220 nm thick and had been etched and ashed. When tantalum pentafluoride (TaF5) is exposed to an unsealed pMSQ sample, X-ray photoelectron spectroscopy (XPS) depth profiling and secondary ion mass spectroscopy (SIMS) depth profiling reveal penetration of Ta into the pores all the way to the pMSQ / Si interface. Boron carbo-nitride films were grown by thermal chemical vapor deposition (CVD) using dimethylamine borane (DMAB) precursor with Ar carrier gas and C2H4 coreactant. These films had a stoichiometry of BC0.9N0.07 and have been shown in a previous study to have a k value as low as 3.8. BC0.9N0.07 films ranging from 1.8 to 40.6 nm were deposited on pMSQ and then exposed to TaF5 gas to determine the extent of Ta penetration into the pMSQ. Ta penetration was determined by XPS depth profiling and sometimes SIMS depth profiling. XPS depth profiling of a TaF5 / 6.3 nm BC0.9N0.07 / pMSQ / Si film stack indicates the attenuation of the Ta signal to < 2 at. % throughout the pMSQ. Backside SIMS of this sample suggests that trace amounts of Ta (< 2 at. %) are due to knock-in by Ar ions used for sputtering. An identical film stack containing 3.9 nm BC0.9N0.07 was also successful at inhibiting Ta penetration even with a 370°C post-TaF5 exposure anneal, suggesting the stability of BC0.9N0.07 to thermal diffusion of Ta. All BC0.9N0.07 films thicker than and including 3.9 nm prevented Ta from penetrating into the pMSQ.

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Sub-nm-Scale Depth Profiling of Nitrogen in NO- and N2-Annealed SiO2/4H-SiC(0001) Structures

Materials Science Forum ◽

10.4028/www.scientific.net/msf.963.226 ◽

2019 ◽

Vol 963 ◽

pp. 226-229

Author(s):

Kidist Moges ◽

Mitsuru Sometani ◽

Takuji Hosoi ◽

Takayoshi Shimura ◽

Shinsuke Harada ◽

...

Keyword(s):

Nitric Oxide ◽

High Temperature ◽

Photoelectron Spectroscopy ◽

Depth Profiling ◽

Annealing Duration ◽

Nanometer Scale ◽

Pure Nitrogen ◽

X Ray ◽

Initial Stage

We demonstrated an x-ray photoelectron spectroscopy (XPS)-based technique to reveal the detailed nitrogen profile in nitrided SiO2/4H-SiC structures with sub-nanometer-scale-resolution. In this work, nitric oxide (NO)- and pure nitrogen (N2)-annealed SiO2/4H-SiC(0001) structures were characterized. The measured results of NO-annealed samples with various annealing duration indicate that preferential nitridation just at the SiO2/SiC interfaces (~0.3 nm) proceeds in the initial stage of NO annealing and a longer duration leads to the distribution of nitrogen in the bulk SiO2 within few nanometers of the interface. The high-temperature N2 annealing was found to induce not only SiO2/SiC interface nitridation similarly to NO annealing but also SiO2 surface nitridation.

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Influence of nitrite on chemical composition of passivation film of steel bars under the coupling effects of carbonization and chloride

Anti-Corrosion Methods and Materials ◽

10.1108/acmm-09-2018-1999 ◽

2019 ◽

Vol 66 (2) ◽

pp. 230-235 ◽

Cited By ~ 1

Author(s):

Junzhe Liu ◽

Jundi Geng ◽

Hui Wang ◽

Mingfang Ba ◽

Zhiming He

Keyword(s):

Chemical Composition ◽

Photoelectron Spectroscopy ◽

Chloride Solution ◽

Layer Structure ◽

Coupling Effects ◽

Content Type ◽

X Ray ◽

Passivation Film ◽

Steel Bars ◽

Micro Structures

Purpose This paper aims to study the influence of NaNO2 on the chemical composition of passivation film. Design/methodology/approach X-ray photoelectron spectroscopy and X-ray diffraction were selected to determine the composition of passivation film of steel bars in mortar. The specimens were exposed to the chloride solution, carbonation environment and the coupling effects of chloride solution and carbonation. The chemical composition and micro structures at 0 and 5 nm from the outer surface of the passivation film of steel bars were analyzed. Findings Results showed that the nitrite inhibitor improved the forming rate of the passivation film and increased the mass ratio of Fe3O4 to FeOOH on the surface of steel bars. The component of Fe3O4 at 5 nm of the steel passivation film was more than that at 0 nm. Sodium ferrite in the pore solution was easily hydrolyzed and then FeOOH was formed. Therefore, due to the nitrite inhibitor, a “double layer structure” of the passivation film was formed to prevent steels bars from corrosion. Originality/value This is original work and may help the researchers further understand the mechanism of rust resistance by nitrite inhibitor.

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