scholarly journals Studies of Buried Layers and Interfaces of Tungsten Carbide Coatings on the MWCNT Surface by XPS and NEXAFS Spectroscopy

2020 ◽  
Vol 10 (14) ◽  
pp. 4736
Author(s):  
Danil Sivkov ◽  
Sergey Nekipelov ◽  
Olga Petrova ◽  
Alexander Vinogradov ◽  
Alena Mingaleva ◽  
...  
Keyword(s):  
Tungsten Carbide ◽  
Outer Surface ◽  
Photoelectron Spectroscopy ◽  
Coating Layer ◽  
Layer Structure ◽  
Charge Compensation ◽  
Material Surface ◽  
X Ray ◽  
Mwcnt Surface ◽  
Nexafs Spectroscopy

Currently, X-ray photoelectron spectroscopy (XPS) is widely used to characterize the nanostructured material surface. The ability to determine the atom distribution and chemical state with depth without the sample destruction is important for studying the internal structure of the coating layer several nanometers thick, and makes XPS the preferable tool for the non-destructive testing of nanostructured systems. In this work, ultra-soft X-ray spectroscopy methods are used to study hidden layers and interfaces of pyrolytic tungsten carbide nanoscale coatings on the multi-walled carbon nanotube (MWCNT) surfaces. XPS measurements were performed using laboratory spectrometers with sample charge compensation, and Near Edge X-ray Absorption Fine Structure (NEXAFS) studies using the Russian–German dipole beamline (RGBL) synchrotron radiation at BESSY-II. The studied samples were tested by scanning and transmission electron microscopy, X-ray diffractometry, Raman scattering and NEXAFS spectroscopy. It was shown that the interface between MWCNT and the pyrolytic coating of tungsten carbide has a three-layer structure: (i) an interface layer consisting of the outer graphene layer carbon atoms, forming bonds with oxygen atoms from the oxides adsorbed on the MWCNT surface, and tungsten atoms from the coating layer; (ii) a non-stoichiometric tungsten carbide WC1-x nanoscale particles layer; (iii) a 3.3 nm thick non-stoichiometric tungsten oxide WO3-x layer on the WC1-x/MWCNT nanocomposite outer surface, formed in air. The tungsten carbide nanosized particle’s adhesion to the nanotube outer surface is ensured by the formation of a chemical bond between the carbon atoms from the MWCNT upper layer and the tungsten atoms from the coating layer.

scholarly journals The Identification of Cu–O–C Bond in Cu/MWCNTs Hybrid Nanocomposite by XPS and NEXAFS Spectroscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2993
Author(s):  
Danil V. Sivkov ◽  
Olga V. Petrova ◽  
Sergey V. Nekipelov ◽  
Alexander S. Vinogradov ◽  
Roman N. Skandakov ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Photoelectron Spectroscopy ◽  
Charge Compensation ◽  
X Ray ◽  
Nexafs Spectroscopy ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Complementary Set ◽  
Walled Carbon Nanotubes ◽  
X Ray Absorption

The results of the research of a composite based on multi-walled carbon nanotubes (MWCNTs) decorated with CuO/Cu2O/Cu nanoparticles deposited by the cupric formate pyrolysis are discussed. The study used a complementary set of methods, including scanning and transmission electron microscopy, X-ray diffractometry, Raman, and ultrasoft X-ray spectroscopy. The investigation results show the good adhesion between the copper nanoparticles coating and the MWCNT surface through the oxygen atom bridge formation between the carbon atoms of the MWCNT outer graphene layer and the oxygen atoms of CuO and Cu2O oxides. The formation of the Cu–O–C bond between the coating layer and the outer nanotube surface is clearly confirmed by the results of the O 1s near edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) of the Cu/MWCNTs nanocomposite. The XPS measurements were performed using a laboratory spectrometer with sample charge compensation, and the NEXAFS studies were carried out using the synchrotron radiation of the Russian–German dipole beamline at BESSY-II (Berlin, Germany) and the NanoPES station at the Kurchatov Center for Synchrotron Radiation and Nanotechnology (Moscow, Russia).

High Temperature Oxidation Behavior of SUS310S Austenitic Stainless Steel

2014 ◽  
Vol 941-944 ◽  
pp. 212-215
Author(s):  
Tao Zheng ◽  
Jing Tao Han
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxidation Behavior ◽  
Layer Structure ◽  
Energy Dispersive Spectrometer ◽  
Austenitic Stainless Steels ◽  
Temperature Oxidation ◽  
X Ray ◽  
High Temperature Oxidation Behavior ◽  
High Oxidation Resistance ◽  
Ray Diffusion

The oxidation behavior of SUS310S austenitic stainless steels was studied in isothermal conditions at different temperatures between 800oC and 1100oC for 96h in air. The oxidation kinetics was analyzed, the surface and cross-section of the oxide scale grown by oxidation were characterized by using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffusion (XRD) and X-ray photoelectron spectroscopy (XPS). The SUS310S steel has high oxidation resistance at 800oC and with the increase of the temperature, the parabolic rate constants is constantly increasing. Examination of the morphology and composition of oxide layers reveals a double-layer structure, The inner layer is mainly chromium oxide (Cr2O3) and is covered by an uneven thinness outer layer of manganese-chromium or iron-chromium spinel oxide.

The Surface Modification and Characteristics of Useful Expanded PTFE Composites by Photo-Radiation Methods

2013 ◽  
Vol 690-693 ◽  
pp. 1636-1640 ◽  
Author(s):  
Te Hsing Wu ◽  
Ko Shao Chen ◽  
Lie Hang Shen
Keyword(s):  
Contact Angle ◽  
Acetic Acid ◽  
Photoelectron Spectroscopy ◽  
Plasma Deposition ◽  
Material Surface ◽  
Water Contact ◽  
X Ray ◽  
Hydrogel Film ◽  
Γ Ray ◽  
Ptfe Composites

In this study, We immobilized hydrogel material onto expanded polytetrafluoroethylene (ePTFE) film and used as an functional biomaterial. The material is a film containing titanium oxide onto polymer sheet. The hydrogel film is hydrophilic, bacterial inactivated and bio-compatible. In order to improve the ePTFE film biocompatibility, the cold plasma or γ-ray technology was used with acetic acid as monomer to deposit onto ePTFE film and then (N-isopropylacrylamide) was grafted onto the surface by radiation photo-grafting. The characteristics of the material surface were evaluated with X-ray photoelectron spectroscopy (XPS), FTIR and water contact angle. It was found that the contact angle of water on the untreated ePTFE significantly decrease from125° to 72° after ePTFE film being treated with acetic acid plasma deposition procedure. Due to the hydrophilicity of poly (N-isopropylacrylamide), so the contact angle of water on the ePTFE-g-NIPAAm almost approached to 0°. This thermal sensitive ePTFE hydrogels can be applied to artificial guiding tube and wound dressing material.

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

2019 ◽  
Vol 66 (2) ◽  
pp. 230-235 ◽  
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.

The Electronic Structures of Fullerene/Transition-Metal Hybrid Material

2008 ◽  
Vol 1081 ◽  
Author(s):  
Yoshihiro Matsumoto ◽  
Seiji Sakai ◽  
Hiroshi Naramoto ◽  
Norie Hirao ◽  
Yuji Baba ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electronic Structures ◽  
Line Broadening ◽  
Hybrid Films ◽  
Xps Spectra ◽  
X Ray ◽  
Nexafs Spectroscopy ◽  
Homo Level ◽  
Valence Band Region ◽  
X Ray Absorption

ABSTRACTLocal electronic structures of C60-Co hybrid films have been studied by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. XPS spectra of C 1s main and satellite peaks for the C60-Co films show binding-energy shifts and also line-broadening compared to those in a pure C60 film. In addition, XPS spectra in valence band region suggest an appearance of three new components at near Fermi level and HOMO level in the C60-Co film. These results are attributed to hybridizations between Co 3d band and C60 LUMO. The same effects have been observed in NEAXFS spectra at C 1s excitations.

scholarly journals On the Influence of Composition and Structure of Carbon-Supported Pt-SnO2 Hetero-Clusters onto Their Electrocatalytic Activity and Durability in PEMFC

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 803 ◽  
Author(s):  
Spasov ◽  
Ivanova ◽  
Pushkarev ◽  
Pushkareva ◽  
Presnyakova ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Photoelectron Spectroscopy ◽  
Layer Structure ◽  
Polymer Electrolyte Membrane ◽  
Carbon Support ◽  
Reduction Reaction ◽  
Support Surface ◽  
Catalytic Layer ◽  
X Ray ◽  
Electrolyte Membrane

A detailed study of the structure, morphology and electrochemical properties of Pt/C and Pt/x-SnO2/C catalysts synthesized using a polyol method has been provided. A series of catalysts supported on the SnO2-modified carbon was synthesized and studied by various methods including transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical methods, and fuel cell testing. The SnO2 content varies from 5 to 40 wt %. The TEM images, XRD and XPS analysis suggested the Pt-SnO2 hetero-clusters formation. The SnO2 content of ca. 10% ensures an optimal catalytic layer structure and morphology providing uniform distribution of Pt-SnO2 clusters over the carbon support surface. Pt/10wt %-SnO2/C catalyst demonstrates increased activity and durability toward the oxygen reduction reaction (ORR) in course of accelerated stress testing due to the high stability of SnO2 and its interaction with Pt. The polymer electrolyte membrane fuel cell current–voltage performance of the Pt/10wt %-SnO2/C is comparable with those of Pt/C, however, higher durability is expected.

Characterisation of Al coordination at the outer surface of dealuminated mordenites by X-ray photoelectron spectroscopy

1993 ◽  
Vol 2 (1) ◽  
pp. 7-15 ◽  
Author(s):  
M.J. Remy ◽  
M.J. Genet ◽  
P.P. Notté ◽  
P.F. Lardinois ◽  
G. Poncelet
Keyword(s):  
Outer Surface ◽  
Photoelectron Spectroscopy ◽  
X Ray

scholarly journals Photolysis of Fluorinated Graphites with Embedded Acetonitrile Using a White-Beam Synchrotron Radiation

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 231
Author(s):  
Galina I. Semushkina ◽  
Yuliya V. Fedoseeva ◽  
Anna A. Makarova ◽  
Dmitry A. Smirnov ◽  
Igor P. Asanov ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Photoelectron Spectroscopy ◽  
X Ray ◽  
Photon Irradiation ◽  
Nexafs Spectroscopy ◽  
White Beam ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
X Ray Absorption

Fluorinated graphitic layers with good mechanical and chemical stability, polar C–F bonds, and tunable bandgap are attractive for a variety of applications. In this work, we investigated the photolysis of fluorinated graphites with interlayer embedded acetonitrile, which is the simplest representative of the acetonitrile-containing photosensitizing family. The samples were continuously illuminated in situ with high-brightness non-monochromatized synchrotron radiation. Changes in the compositions of the samples were monitored using X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The NEXAFS N K-edge spectra showed that acetonitrile dissociates to form HCN and N2 molecules after exposure to the white beam for 2 s, and the latter molecules completely disappear after exposure for 200 s. The original composition of fluorinated matrices CF0.3 and CF0.5 is changed to CF0.10 and GF0.17, respectively. The highly fluorinated layers lose fluorine atoms together with carbon neighbors, creating atomic vacancies. The edges of vacancies are terminated with the nitrogen atoms and form pyridinic and pyrrolic units. Our in situ studies show that the photolysis products of acetonitrile depend on the photon irradiation duration and composition of the initial CFx matrix. The obtained results evaluate the radiation damage of the acetonitrile-intercalated fluorinated graphites and the opportunities to synthesize nitrogen-doped graphene materials.

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