The Surface Analysis of Nickel Chromia Catalysts by X-Ray Photoelectron Spectroscopy

1973 ◽  
Vol 51 (10) ◽  
pp. 1670-1672 ◽  
Author(s):  
Norman Stewart McIntyre ◽  
Norman Henry Sagert ◽  
Rita Mary Louise Pouteau ◽  
Warren George Proctor
Keyword(s):  
Valence Band ◽  
Surface Analysis ◽  
Photoelectron Spectroscopy ◽  
Isotope Exchange ◽  
Surface Composition ◽  
X Ray ◽  
Hydrogen Water ◽  
Band Spectra ◽  
Composition Changes

The surface composition of a series of nickel–chromia catalysts has been examined by X-ray photoelectron spectroscopy. Correlation of the amount of available surface nickel with the activity of the particular catalyst for hydrogen water deuterium isotope exchange is very good. No significant alterations are observed in the valence band spectra as the surface composition changes.

Effects of Potassium Chemisorption on the Electronic Structure of VxOy/TiO2 Surfaces

1996 ◽  
Vol 454 ◽  
Author(s):  
Fulvio Parmigiani ◽  
Laura E. Depero ◽  
Luigi Sangaletti
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Open Shell ◽  
Band Edge ◽  
X Ray ◽  
Core Line ◽  
Band Spectra ◽  
Gap States ◽  
Vanadium Ions

ABSTRACTX-ray photoelectron spectroscopy of pure and K chemisorbed VxOy/TiO2 powders are reported. Core-line and valence band spectra suggest the presence of vanadium open shell ions on the pure VxOy/TiO2 interface, whereas potassium vanadate seems to form after K chemisorption. That results in the presence of a significant amount of gap states, with vanadium character, just above the O2p band edge, for the pure VxOy/TiO2 powder, while K chemisorption, reducing significantly the open shell vanadium ions, quenches the gap emission in the XPS valence band spectra.

Dissolution of UO2(s) in MgCl2-Brines Under Different Redox Conditions.

1992 ◽  
Vol 294 ◽  
Author(s):  
Ignasi Casas ◽  
J. Gimenez ◽  
J. De Pablo ◽  
M.E. Torrero
Keyword(s):  
Dissolution Rate ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Initial Increase ◽  
X Ray ◽  
Reducing Conditions ◽  
Subsequent Decrease ◽  
Partial Pressures ◽  
Composition Changes ◽  
Initial Dissolution Rate

ABSTRACTThe dissolution of unirradiated UO2(s), with a particle size of 1 mm, has been studied in MgCl2 brines at 298 K under both reducing and oxidizing conditions. Results obtained under reducing conditions (H atmosphere in the presence of a palladium catalyst) show an initial increase of the total uranium concentration in solution and a subsequent decrease until equilibrium (or steady state) values are reached. Results obtained under oxidizing conditions (nominal oxygen partial pressures of 0.05, 0.21 and 1 atm) show two different trends. A relatively fast initial dissolution rate and, after approximately two or three weeks, a slower dissolution rate. X-Ray Photoelectron Spectroscopy (XPS) has shown that the UO2 surface composition changes during the experiment.

Characterization of Surface Composition and Microstructure of H21 Steel Implanted Using Masking Ti-Implantation

2011 ◽  
Vol 228-229 ◽  
pp. 130-134
Author(s):  
Jian Hua Yang ◽  
Song Li
Keyword(s):  
Wear Resistance ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
X Ray Diffraction ◽  
Interference Microscope ◽  
X Ray ◽  
Concentration Depth Profile ◽  
Surface Oxides ◽  
Composition Changes

Ti ions were implanted into H21 steel to improve the surface structure of oxides in H21 steel. The wear characteristics of the implanted steel was measured and compared to the performance of the un-implanted steel by a line-cutting apparatus and an optical interference microscope. The Ti concentration depth profile of the implanted steel was measured by Rutherford backscattering spectroscopy (RBS). The structure and composition of oxides were analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The results showed that the improved wear resistance of the implanted steel was mainly due to the structure and composition changes of the surface oxides after Ti ion implantation.

X-Ray Photoelectron Spectroscopic Studies of Carbon Fiber Surfaces. Part XVI: Core-Level and Valence-Band Studies of Pitch-Based Fibers Electrochemically Treated in Ammonium Carbonate Solution

1992 ◽  
Vol 46 (4) ◽  
pp. 645-651 ◽  
Author(s):  
Yaoming Xie ◽  
Tiejun Wang ◽  
Oliver Franklin ◽  
Peter M. A. Sherwood
Keyword(s):  
Carbon Fiber ◽  
Valence Band ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Treatment Time ◽  
Spectroscopic Studies ◽  
Core Level ◽  
Short Treatment ◽  
X Ray ◽  
Band Spectra

DuPont E-120 high-modulus pitch-based carbon fibers were treated electrochemically in 0.5 M (NH4)2CO3 solution under both potentiostatic and galvanostatic modes. X-ray photoelectron spectroscopy (XPS) was used to monitor the chemical changes on the carbon fiber surfaces. Both core-level and valence-band spectra showed that the treatment introduced both oxygen-containing and nitrogen-containing functional groups onto the fiber surfaces, and the mainly oxygen-containing functional groups produced were carbonyl (C=O) type functional groups after longer treatment time. For short treatment time, hydroxide (C-OH) type groups were the dominant functionality, and ether (C-O-C) or epoxide type groups were also formed. The O 2 s peaks from oxygen atoms in the hydroxide functionality and the ether or epoxide groups are well separated in the valence-band spectra; the corresponding O 1 s peaks, however, are not separated in the O 1 s core-region spectra.

CO2 Reduction to Propanol by Copper Foams: A Pre- and Post-Catalysis Study

2020 ◽  
Author(s):  
Jennifer A. Rudd ◽  
Ewa Kazimierska ◽  
Louise B. Hamdy ◽  
Odin Bain ◽  
Sunyhik Ahn ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Photoelectron Spectroscopy ◽  
Carbon Capture ◽  
Surface Composition ◽  
Co2 Reduction ◽  
Structural Rearrangement ◽  
Copper Electrode ◽  
Ex Situ ◽  
X Ray ◽  
Copper Electrodes

The utilization of carbon dioxide is a major incentive for the growing field of carbon capture. Carbon dioxide could be an abundant building block to generate higher value products. Herein, we describe the use of porous copper electrodes to catalyze the reduction of carbon dioxide into higher value products such as ethylene, ethanol and, notably, propanol. For <i>n</i>-propanol production, faradaic efficiencies reach 4.93% at -0.83 V <i>vs</i> RHE, with a geometric partial current density of -1.85 mA/cm<sup>2</sup>. We have documented the performance of the catalyst in both pristine and urea-modified foams pre- and post-electrolysis. Before electrolysis, the copper electrode consisted of a mixture of cuboctahedra and dendrites. After 35-minute electrolysis, the cuboctahedra and dendrites have undergone structural rearrangement. Changes in the interaction of urea with the catalyst surface have also been observed. These transformations were characterized <i>ex-situ</i> using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. We found that alterations in the morphology, crystallinity, and surface composition of the catalyst led to the deactivation of the copper foams.

Surface Analysis by X-ray Photoelectron Spectroscopy of Sol−Gel Silica Modified with Covalently Bound Peptides

2007 ◽  
Vol 111 (40) ◽  
pp. 11850-11857 ◽  
Author(s):  
Sabrina S. Jedlicka ◽  
Jenna L. Rickus ◽  
Dmitry Y. Zemlyanov
Keyword(s):  
Surface Analysis ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
X Ray ◽  
Covalently Bound
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