Organic carbon at soil particle surfaces-evidence from x-ray photoelectron spectroscopy and surface abrasion

2002 ◽  
Vol 66 (5) ◽  
pp. 1526-1530 ◽  
Author(s):  
Wulf Amelung ◽  
Klaus Kaiser ◽  
Gerd Kammerer ◽  
Gustav Sauer
Keyword(s):  
Organic Carbon ◽  
Photoelectron Spectroscopy ◽  
Soil Particle ◽  
X Ray

scholarly journals Supplementary research of clinoptilolite-rich tuff composites after adsorption trials using the XPS technique

2006 ◽  
Vol 4 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Eva Chmielewská ◽  
Wlodzimierz Tylus ◽  
Marcela Morvová
Keyword(s):  
Organic Carbon ◽  
Aqueous Solutions ◽  
Photoelectron Spectroscopy ◽  
External Surface ◽  
Zeolite Surface ◽  
X Ray ◽  
Surface Modified ◽  
Modified Clinoptilolite

AbstractThe paper deals with fabrication of carbonized and hydrophobized clinoptilolite-rich tuff using organic carbon rich substances, here particularly starch and waste vegetable residues, which were pyrolytically combusted and covered the external zeolite surface. Hydrophobization of the zeolite external surface was accomplished by octadecylammonium surfactant. Both surface modified clinoptilolite-rich tuffs were tested and compared with each other with regard to removal of organic (phenol) and inorganic (chromate, arsenate) pollutants from aqueous solutions. These elaborated composites with surface adsorbed pollutant species were analysed by X-ray photoelectron spectroscopy (XPS).

X-RAY Photoelectron Spectroscopic Study of Cigar Lake Uranium Ore: A Natural Analog for Used Fuel

1991 ◽  
Vol 257 ◽  
Author(s):  
S. Sunder ◽  
J.J. Cramer ◽  
N.H. Miller
Keyword(s):  
High Resolution ◽  
Organic Carbon ◽  
Photoelectron Spectroscopy ◽  
Uranium Deposit ◽  
Radioactive Decay ◽  
Xps Spectra ◽  
X Ray ◽  
Natural Analog ◽  
Cutting Processes ◽  
Nuclear Fuel Waste

ABSTRACTX-ray photoelectron spectroscopy (XPS) was used to study samples from the Cigar Lake uranium deposit in northern Saskatchewan. Two uranium-rich sections, CS-615 and CS-620 were studied. Peaks due to U, 0, C, Pb, Si, Ca, Al, S, Cu and Th were seen in the XPS spectra. Concentrations of Pb of up to 14 wt% were measured by XPS and correspond to the Pb ingrowth by radioactive decay during the 1.3 billion years since the ore was formed. High-resolution spectra were recorded for the U, Pb, 0, and C bands. Lead was in the +2 oxidation state in all samples. The carbon signal indicated the presence of organic carbon, while the oxygen bands indicated the presence of significant amounts of water in the samples. The samples from the CS-615 section had U6+/U4+ ratios between 0.16 and 0.29. However, the U6+/U4+ ratios for section CS-620 were about 0.7 but this is attributed to oxidation of the ore by water during the drilling and cutting processes. The significance of the results for disposal concepts in nuclear fuel waste management programs is discussed.

Two dimensional Sr silicate grown on Si(001) studied using X-ray Photoelectron Spectroscopy

2006 ◽  
Vol 132 ◽  
pp. 87-90
Author(s):  
M. El Kazzi ◽  
G. Delhaye ◽  
S. Gaillard ◽  
E. Bergignat ◽  
G. Hollinger
Keyword(s):  
Photoelectron Spectroscopy ◽  
Two Dimensional ◽  
X Ray

BONDS IN AMORPHOUS Nb1-xSixSTUDIED BY X-RAY EMISSION AND X-RAY PHOTOELECTRON SPECTROSCOPY

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-1025-C9-1028 ◽  
Author(s):  
W. ZAHOROWSKI ◽  
A. SIMUNEK ◽  
G. WIECH ◽  
K. SÖLDNER ◽  
R. KNAUF ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
X Ray

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

Interactions of Ge Atoms with High- ê Oxide Dielectric Surfaces

2005 ◽  
Vol 879 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt
Keyword(s):  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Tungsten Filament ◽  
X Ray ◽  
Dielectric Surfaces ◽  
Temperature Programmed ◽  
The Stability ◽  
Ge Nanocrystals

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.

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.

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