scholarly journals XPS Studies of the Initial Oxidation of Polycrystalline Rh Surface

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 617
Author(s):  
Marek Trzcinski ◽  
Grażyna Balcerowska-Czerniak ◽  
Antoni Bukaluk
Keyword(s):  
Statistical Analysis ◽  
Crystallographic Orientation ◽  
Photoelectron Spectroscopy ◽  
Oxidation Process ◽  
Multivariate Statistical ◽  
Initial Oxidation ◽  
X Ray ◽  
Electron Backscattering Diffraction ◽  
The Individual ◽  
Ebsd Method

Increased interest in the oxidation process of polycrystalline rhodium, observed in recent years, is the result of its application in exhaust catalytic converters. However, most studies have involved sample surfaces with low Miller indices. In our research, we investigated polycrystalline rhodium foil containing crystallographically different, highly stepped, µm-sized crystallites. These crystallites were exposed to identical oxidizing conditions. To determine crystallographic orientation, the electron backscattering diffraction (EBSD) method was used. To investigate the initial stages of oxidation on the individual crystallites of Rh, X-ray photoelectron spectroscopy (XPS) studies were performed. The results obtained for the individual crystallites were compared and analyzed using chemical state quantification of XPS data and multivariate statistical analysis (MVA).

scholarly journals Chemical Species, Micromorphology, and XRD Fingerprint Analysis of Tibetan MedicineZuotaiContaining Mercury

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Cen Li ◽  
Hongxia Yang ◽  
Yuzhi Du ◽  
Yuancan Xiao ◽  
Zhandui ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Multivariate Statistical Analysis ◽  
Chemical Species ◽  
Physicochemical Characteristics ◽  
Chemical Substance ◽  
Tibetan Medicine ◽  
Fingerprint Analysis ◽  
Multivariate Statistical ◽  
Positive Role ◽  
X Ray

Zuotai(gTso thal) is one of the famous drugs containing mercury in Tibetan medicine. However, little is known about the chemical substance basis of its pharmacodynamics and the intrinsic link of different samples sources so far. Given this, energy dispersive spectrometry of X-ray (EDX), scanning electron microscopy (SEM), atomic force microscopy (AFM), and powder X-ray diffraction (XRD) were used to assay the elements, micromorphology, and phase composition of nineZuotaisamples from different regions, respectively; the XRD fingerprint features ofZuotaiwere analyzed by multivariate statistical analysis. EDX result shows thatZuotaicontains Hg, S, O, Fe, Al, Cu, and other elements. SEM and AFM observations suggest thatZuotaiis a kind of ancient nanodrug. Its particles are mainly in the range of 100–800 nm, which commonly further aggregate into 1–30 μm loosely amorphous particles. XRD test shows thatβ-HgS, S8, andα-HgS are its main phase compositions. XRD fingerprint analysis indicates that the similarity degrees of nine samples are very high, and the results of multivariate statistical analysis are broadly consistent with sample sources. The present research has revealed the physicochemical characteristics ofZuotai, and it would play a positive role in interpreting this mysterious Tibetan drug.

Reconstructed Structure of SiO2/Si(111) Interface

1990 ◽  
Vol 208 ◽  
Author(s):  
Ichiro Hirosawa ◽  
Jun'ichiro Nizuki ◽  
Toru Tatsumi ◽  
Koichi Akimoto ◽  
Junji Matsui
Keyword(s):  
Molecular Beam ◽  
Structural Model ◽  
Oxidation Process ◽  
Grazing Incidence ◽  
Interface Structure ◽  
X Ray Diffraction ◽  
Initial Oxidation ◽  
X Ray ◽  
Diffraction Geometry ◽  
Symmetry Structure

ABSTRACTIn order to investigate the initial oxidation process Qf the Si (111) surface, we have studied the molecular beam deposited Si0 2/Si(111)-7×7 interface structure using grazing incidence X-ray diffraction geometry. We suggest a three-fold symmetry structural model composed of stacking fault layer, dimer layer and additional ordered atoms. The three-fold symmetry structure comes from the preference for oxidation in the faulted half of the 7×7 structure.

Ellipsometric and XPS Studies of 4H-SiC/SiO2 Interfaces, and Sacrificial Oxide Stripped 4H-SiC Surfaces

2006 ◽  
Vol 527-529 ◽  
pp. 1027-1030 ◽  
Author(s):  
Owen J. Guy ◽  
L. Chen ◽  
G. Pope ◽  
K.S. Teng ◽  
T. Maffeis ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Interfacial Layer ◽  
Oxidation Process ◽  
Silicon Layer ◽  
Subsequent Removal ◽  
X Ray ◽  
Mos Devices ◽  
Device Processing ◽  
Form Features ◽  
Silicon Oxygen

The investigation of the silicon carbide surface after a sacrificial silicon oxidation technique is reported. Oxidation of SiC is a necessary step in the fabrication of MOS devices and device termination features such as field plates. Device processing requires the etching of windows through the oxide layer to form features such as metal / SiC contacts. However, this work indicates that a thin interfacial Si-O-C layer is still present after etching the oxide with hydrofluric acid (HF). Ellipsometry and X-ray photoelectron spectroscopy (XPS) have been used to evaluate this interfacial layer formed after oxide growth and after subsequent removal of oxide layers. An XPS analysis of the surface after removal of the oxide revealed that silicon, oxygen and carbon were all present in the remaining layer, which could not be removed by annealing at temperatures up to 1000°C. The Si-O-C layer could be eliminated by altering the oxidation conditions or by using a sacrificial silicon layer oxidation process. Ni Schottky barrier diodes fabricated on the 4H-SiC surface after removal of the oxide, displayed slightly higher ideality factors than those of diodes fabricated on untreated 4H-SiC samples.

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

BBonding in minerals: the application of PAX (photoelectron and X-ray) spectroscopy to the direct determination of electronic structure

1989 ◽  
Vol 53 (370) ◽  
pp. 153-164 ◽  
Author(s):  
David S. Urch
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Direct Determination ◽  
Energy Scale ◽  
X Ray ◽  
Electron Transitions ◽  
Dipole Selection Rule ◽  
The Individual

AbstractX-ray photoelectron spectroscopy can be used to measure the ionization energies of electrons in both valence band and core orbitals. As core vacancies are the initial states for X-ray emission, a knowledge of their energies for all atoms in a mineral enables all the X-ray spectra to be placed on a common energy scale. X-ray spectra are atom specific and are governed by the dipole selection rule. Thus the individual bonding roles of the different atoms are revealed by the fine structure of valence X-ray peaks (i.e. peaks which result from electron transitions between valence band orbitals and core vacancies). The juxtaposition of such spectra enables the composition of the molecular orbitals that make up the chemical bonds of a mineral to be determined.Examples of this approach to the direct determination of electronic structure are given for silica, forsterite, brucite, and pyrite. Multi-electron effects and developments involving anisotropic X-ray emission from single crystals are also discussed.

scholarly journals Multivariate Statistical Analysis of Particle X-ray Spectra

1998 ◽  
Vol 4 (S2) ◽  
pp. 202-203
Author(s):  
Ian M. Anderson ◽  
John A. Small
Keyword(s):  
Statistical Analysis ◽  
Trace Element ◽  
Multivariate Statistical Analysis ◽  
A Priori ◽  
Detectable Level ◽  
Multivariate Statistical ◽  
Raw Data ◽  
X Ray ◽  
Carbon Substrates ◽  
Particle Spectra

Multivariate statistical analysis (MSA) is a powerful tool for the analysis of series of spectra. This paper explores an application of MSA to a series of energy dispersive X-ray (EDX) spectra acquired in the scanning electron microscope (SEM) from a series of particles. The raw data were series of spectra previously acquired to test analytical procedures for trace element detection. This paper explores the possibility of performing the trace element detection with MSA components that have been extracted from the raw data without any a priori assumptions about the information content of the particle spectra. Particles were prepared from two analytical glasses, dispersed onto carbon substrates and coated with carbon. The compositions of the two glasses are substantially similar, except that one glass (K-3106) contains 0.7 wt.% Fe, whereas the other glass (K-3069) does not contain Fe at a detectable level.

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