The Surface Oxidation of Cobaltite

1987 ◽  
Vol 40 (2) ◽  
pp. 231 ◽  
Author(s):  
AN Buckley
Keyword(s):  
Liquid Nitrogen ◽  
Photoelectron Spectroscopy ◽  
Surface Oxidation ◽  
Dilute Acid ◽  
Ambient Conditions ◽  
Initial Oxidation ◽  
X Ray ◽  
Mineral Sample ◽  
Oxidation In Air ◽  
Aqueous Conditions

The oxidation of cobaltite, CoAsS, has been investigated by X-ray photoelectron spectroscopy. Products of the initial oxidation in air were deduced from surfaces abraded under liquid nitrogen rather than fracture surfaces, as fracture of the mineral sample studied took place preferentially along interfaces at which oxidized material was already present. Cobalt and arsenic oxides are formed in air under ambient conditions; however, sulfur is not involved in the initial oxidation. In air-saturated dilute acid, an oxidized layer is retained at the surface of cobaltite ore particles. Under similar aqueous conditions, pyrite, from which cobaltite often has to be separated, remains free of hydrophilic species.

Characterization of Ge1-x-ySixSny Ternary Alloy Surfaces and Ni/Ge1-x-ySixSny Bilayer Reactions by X-Ray Techniques

2015 ◽  
Vol 1770 ◽  
pp. 19-24 ◽  
Author(s):  
Gordon J. Grzybowski ◽  
Arnold Kiefer ◽  
Bruce Claflin
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Shifts ◽  
Surface Oxidation ◽  
Device Fabrication ◽  
Ternary Alloys ◽  
Ambient Conditions ◽  
X Ray ◽  
Wide Range ◽  
Xps Characterization

ABSTRACTInterest in next generation devices that integrate photonic and electronic functionality is focused on extending the capability of existing group IV material systems while maintaining compatibility with existing processing methods and procedures. One such class of materials which has been recently developed, Ge1-x-ySixSny ternary alloys, is being investigated for integrated Si photonics, solar cell materials, telecommunication applications, and for IR photodetectors. These alloys afford the opportunity to decouple the band gap energies and lattice constants over a wide range of values, potentially yielding direct and indirect character that can be coupled with a variety of different substrates dependent on composition.In the present work, we report X-ray photoelectron spectroscopy (XPS) characterization of Ge1-x-ySixSny alloys grown by gas-source molecular beam epitaxy (GS-MBE) and investigate Ni- Ge1-x-ySiySny bilayer reactions with x-ray diffraction (XRD). The surface oxidation of samples stored in ambient conditions were measured with XPS. High resolution spectra showed chemical shifts of Ge, Si and Sn peaks consistent with Ge-O, Si-O and Sn-O bond formation. Depth profiling indicates a homogeneous composition throughout the bulk of the sample with surface oxidation confined to the top few nanometers. A highly tin-enriched layer was indicated at the surface of the material, while silicon was observed to be either enriched or depleted at the surface depending on the sample.To study the interaction of the ternary with an ohmic contact commonly used in device fabrication processes today, nickel layers 30 nm thick were evaporated onto the alloys and were annealed in nitrogen up to 400 °C for periods as long as 1 hour. The XRD data show that the Ni2(Ge1-x-ySixSny) phase forms first followed by Ni(Ge1-x-ySixSny).

Surface Oxidation of Si (111) By High Purity Ozone and Negative Ions Produced by Rydberg Electron Transfer

1996 ◽  
Vol 446 ◽  
Author(s):  
H. Nonaka ◽  
A. Kurokawa ◽  
K. Nakamura ◽  
S. Ichimura
Keyword(s):  
Electron Transfer ◽  
High Purity ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Surface Oxidation ◽  
Negative Ions ◽  
High Flux ◽  
Initial Oxidation ◽  
X Ray ◽  
Rydberg Electron

AbstractThe sub‐initial oxidation of Si (111) surface by a high‐flux pure ozone was investigated using X‐ray photoelectron spectroscopy. In addition to the advantage of the pure ozone which can efficiently oxidize the Si surface at room temperature, the high‐flux ozone was found to further enhance the oxidation. The possibility of producing negative ions of oxidizing gases using Rydberg electron transfer was also investigated.

scholarly journals Non-Thermal Plasma-Modified Ru-Sn-Ti Catalyst for Chlorinated Volatile Organic Compound Degradation

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1456
Author(s):  
Yujie Fu ◽  
You Zhang ◽  
Qi Xin ◽  
Zhong Zheng ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Surface Oxidation ◽  
Treatment Method ◽  
X Ray ◽  
Chlorinated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Doped Titania

Chlorinated volatile organic compounds (CVOCs) are vital environmental concerns due to their low biodegradability and long-term persistence. Catalytic combustion technology is one of the more commonly used technologies for the treatment of CVOCs. Catalysts with high low-temperature activity, superior selectivity of non-toxic products, and resistance to chlorine poisoning are desirable. Here we adopted a plasma treatment method to synthesize a tin-doped titania loaded with ruthenium dioxide (RuO2) catalyst, possessing enhanced activity (T90%, the temperature at which 90% of dichloromethane (DCM) is decomposed, is 262 °C) compared to the catalyst prepared by the conventional calcination method. As revealed by transmission electron microscopy, X-ray diffraction, N2 adsorption, X-ray photoelectron spectroscopy, and hydrogen temperature-programmed reduction, the high surface area of the tin-doped titania catalyst and the enhanced dispersion and surface oxidation of RuO2 induced by plasma treatment were found to be the main factors determining excellent catalytic activities.

Revealing the mechanism of the early stages of Ni–W RABiTS oxidation

2010 ◽  
Vol 25 (12) ◽  
pp. 2362-2370 ◽  
Author(s):  
Andrey V. Blednov ◽  
Oleg Yu. Gorbenko ◽  
Dmitriy P. Rodionov ◽  
Andrey R. Kaul
Keyword(s):  
Internal Oxidation ◽  
Photoelectron Spectroscopy ◽  
Oxidation Mechanism ◽  
Surface Oxidation ◽  
Surface Region ◽  
Near Surface ◽  
Precise Position ◽  
X Ray ◽  
Early Stages ◽  
Phase And Chemical Composition

The early stages of surface oxidation of biaxially textured Ni–W tapes were studied using thermodynamic calculations along with experimental tape oxidation at low P(O2). Tape phase and chemical composition, surface morphology, and roughness were examined using x-ray diffraction (XRD), energy-dispersive x-ray analysis (EDX), secondary ion mass spectroscopy (SIMS), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). For a Ni0.95W0.05 alloy tape, the precise position of the tape oxidation line in P(O2)–T coordinates was established. This line includes a break at T ≈ 650 °C that originates from the change of the W oxidation mechanism from internal oxidation to oxidation on a free surface accompanied by segregation of the alloy components in the tape near-surface region. The surface roughness of a polished tape increased drastically during internal oxidation of W; further tape oxidation did not affect the integral roughness parameters, but introduced numerous small (˜;100 nm) features on the tape surface comprising NiO precipitates.

The initial oxidation of poly-crystalline aluminum studied with x-ray photoelectron spectroscopy

2014 ◽  
Vol 47 (10) ◽  
pp. 105301
Author(s):  
Jiang-Tao Li ◽  
Bart Hoekstra ◽  
Zhen-Bin Wang ◽  
Yi-Kang Pu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Initial Oxidation ◽  
X Ray

scholarly journals Vis-Responsive Copper-Modified Titania for Decomposition of Organic Compounds and Microorganisms

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1194
Author(s):  
Maya Endo-Kimura ◽  
Bariş Karabiyik ◽  
Kunlei Wang ◽  
Zhishun Wei ◽  
Bunsho Ohtani ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Water Oxidation ◽  
Diffuse Reflectance Spectroscopy ◽  
Antimicrobial Properties ◽  
Localized Surface Plasmon ◽  
Intrinsic Activity ◽  
Ambient Conditions ◽  
Copper Species ◽  
X Ray

Seven commercial titania (titanium(IV) oxide; TiO2) powders with different structural properties and crystalline compositions (anatase/rutile) were modified with copper by two variants of a photodeposition method, i.e., methanol dehydrogenation and water oxidation. The samples were characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Although zero-valent copper was deposited on the surface of titania, oxidized forms of copper, post-formed in ambient conditions, were also detected in dried samples. All samples could absorb visible light (vis), due to localized surface plasmon resonance (LSPR) of zero-valent copper and by other copper species, including Cu2O, CuO and CuxO (x:1-2). The photocatalytic activities of samples were investigated under both ultraviolet (UV) and visible light irradiation (>450 nm) for oxidative decomposition of acetic acid. It was found that titania modification with copper significantly enhanced the photocatalytic activity, especially for anatase samples. The prolonged irradiation (from 1 to 5 h) during samples’ preparation resulted in aggregation of copper deposits, thus being detrimental for vis activity. It is proposed that oxidized forms of copper are more active under vis irradiation than plasmonic one. Antimicrobial properties against bacteria (Escherichia coli) and fungi (Aspergillus niger) under vis irradiation and in the dark confirmed that Cu/TiO2 exhibits a high antibacterial effect, mainly due to the intrinsic activity of copper species.

Sign in / Sign up

Export Citation Format

Share Document