X-ray photoelectron spectroscopic study of hydrated aluminas and aluminas

1994 ◽  
Vol 9 (11) ◽  
pp. 2919-2924 ◽  
Author(s):  
Takeshi Tsuchida ◽  
Hideaki Takahashi
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectra ◽  
Molar Ratio ◽  
Oxygen Species ◽  
X Ray ◽  
Atomic Nuclei ◽  
Valence Electrons ◽  
Core Electrons ◽  
Equal Contribution

X-ray photoelectron spectra of hydrated aluminas (boehmite, diaspore, bayerite, and gibbsite), transition aluminas (y, δ, η, θ, X, and k –Al2O3) and corundum (α-Al2O3) have been studied for spectral characterization of each compound. The O1s spectra are shifted 0.2–1.2 eV to higher binding energy (Eb) in the order of α-Al2O3 < boehmite, diaspore < bayerite, gibbsite, and this agrees with the order of bulk OH/Al molar ratio in samples. The Eb and FWHM values of O1s spectra of transition aluminas depend on the ratio OH/O, i.e., the amount of OH− ions chemisorbed on them, and tend to decrease toward those of α-Al2O3 with increasing calcination temperature. Therefore, it is considered that an attracting effect of the proton on valence electrons in the hydroxyl oxygen causes the increased binding energy between core electrons and oxygen atomic nuclei. The broad O1s spectra of boehmite and diaspore can be deconvoluted into equal contribution from the two oxygen species in O2− and OH− ions in their structures.

X-Ray Photoelectron Spectra of Aluminum Oxides: Structural Effects on the “Chemical Shift”

1973 ◽  
Vol 27 (1) ◽  
pp. 1-5 ◽  
Author(s):  
James R. Lindsay ◽  
Harry J. Rose ◽  
William E. Swartz ◽  
Plato H. Watts ◽  
Kenneth A. Rayburn
Keyword(s):  
Hydrogen Bonding ◽  
Binding Energy ◽  
Binding Energies ◽  
Photoelectron Spectra ◽  
Electrostatic Model ◽  
Structural Effects ◽  
Aluminum Oxides ◽  
X Ray ◽  
Structural Differences ◽  
Core Electrons

The aluminum (2p) electron spectra of several anhydrous and “hydrous” aluminum oxides have been recorded, and the binding energies have been measured. A simple electrostatic model is employed to explain the observed shift in binding energy and relate it to differences in structure and hydrogen bonding. Two conclusions can be drawn: structural differences must be considered when interpreting photoelectron spectra for inorganic crystalline substances; and hydrogen bonding with anions may have a measurable effect on the binding energy of core electrons of the cations.

scholarly journals Characterization of Ti/SnO2 Interface by X-ray Photoelectron Spectroscopy

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 202
Author(s):  
Miranda Martinez ◽  
Anil R. Chourasia
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Chemical Interaction ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Increasing Trend ◽  
Substrate Temperatures ◽  
Beam Technique

The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. The relative percentages of the constituents at the interface have been estimated by curve fitting the spectral data with the corresponding elemental and the oxide spectra. In the 200 °C samples, thermal diffusion of the titanium overlayer was observed. This resulted in the complete oxidation of the titanium overlayer to TiO2 upto a thickness of 0.9 nm of the overlayer. Elemental titanium resulting from the unreacted overlayer was observed to be more in the room temperature samples. The room temperature samples showed variation around 20% for the Ti-suboxide while an increasing trend was observed in the 200 °C samples.

Synthesis and Characterization of Cr (III) Macrocyclic Schiff Base Complexes

2021 ◽  
pp. 269-274
Author(s):  
Dharmendra Kumar Sahu ◽  
Shekhar Srivastava
Keyword(s):  
Schiff Base ◽  
Molar Conductance ◽  
Photoelectron Spectra ◽  
Schiff Base Complexes ◽  
Squaric Acid ◽  
Schiff Base Ligands ◽  
X Ray ◽  
Trimesic Acid ◽  
Macrocyclic Schiff Base

Ninety Cr(III) macrocyclic Schiff base complexes of the type [CrL_n^(1-10) X_2 ]X(Where X = Cl- or NO-3 or CH3COO- and = macrocyclic Schiff base ligands derived from condensation of trimesic acid or p-phthalic acid or squaric acid with different aliphatic diamines) have been synthesised and characterised by elemental analysis; molar conductance; electronic spectra; IR; magnetic moment and XPS i.e. X-ray Photoelectron spectra data. An octahedral geometry was established for them.

Stability of sodalite relative to nepheline in NaCl–H2O brines at 750 °C: Implications for hydrothermal formation of sodalite

2020 ◽  
Vol 58 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Jonathan B. Schneider ◽  
David M. Jenkins
Keyword(s):  
Infrared Spectroscopy ◽  
Constant Temperature ◽  
Molar Ratio ◽  
Standard State ◽  
X Ray Diffraction ◽  
Cage Structure ◽  
X Ray ◽  
Brine Concentration

ABSTRACT Formation of the feldspathoid sodalite (Na6Al6Si6O24·2NaCl) by reaction of nepheline (NaAlSiO4) with NaCl-bearing brines was investigated at 3 and 6 kbar and at a constant temperature of 750 °C to determine the brine concentration at which sodalite forms with variation in pressure. The reaction boundary was located by reaction-reversal experiments in the system NaAlSiO4–NaCl–H2O at a brine concentration of 0.16 ± 0.08 XNaCl [= molar ratio NaCl/(NaCl + H2O)] at 3 kbar and at a brine concentration of 0.35 ± 0.03 XNaCl at 6 kbar. Characterization of the sodalite using both X-ray diffraction and infrared spectroscopy after treatment in these brines indicated no obvious evidence of water or hydroxyl incorporation into the cage structure of sodalite. The data from this study were combined with earlier results by Wellman (1970) and Sharp et al. (1989) at lower (1–1.5 kbar) and higher (7–8 kbar) pressures, respectively, on sodalite formation from nepheline and NaCl which models as a concave-down curve in XNaCl – P space. In general, sodalite buffers the concentration of neutral aqueous NaCl° in the brine to relatively low values at P &lt; 4 kbar, but NaCl° increases rapidly at higher pressures. Thermochemical modeling of these data was done to determine the activity of the aqueous NaCl° relative to a 1 molal (m) standard state, demonstrating very low activities (&lt;0.2 m, or 1.2 wt.%) of NaCl° at 3 kbar and lower, but rising to relatively high activities (&gt;20 m, or 54 wt.%) of NaCl° at 6 kbar or higher. The results from this study place constraints on the concentration of NaCl° in brines coexisting with nepheline and sodalite and, because of the relative insensitivity of this reaction to temperature, can provide a convenient geobarometer for those localities where the fluid compositions that formed nepheline and sodalite can be determined independently.

Solvothermal Synthesis and Luminescence Properties of Gd2O2S:RE3+ (RE3+=Eu3+/Tb3+) Hollow Sphere

2019 ◽  
Vol 807 ◽  
pp. 1-10 ◽  
Author(s):  
Guang Xi Xu ◽  
Xiao Tong Sang ◽  
Jing Bao Lian ◽  
Nian Chu Wu ◽  
Xue Zhang
Keyword(s):  
Solvothermal Synthesis ◽  
Solvothermal Method ◽  
Raw Materials ◽  
Hollow Spheres ◽  
Hollow Structure ◽  
Molar Ratio ◽  
Detailed Characterization ◽  
X Ray ◽  
Electronic Microscope

Eu3+ and Tb3+ ions singly activated Gd2O2S hollow spheres have been successfully synthesized via solvothermal method by using Gd (NO3)3, Eu (NO3)3, Tb (NO3)3 and thiourea as raw materials. Detailed characterization of the as-prepared samples were obtained by X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), transmission electronic microscope (TEM) and photoluminescence (PL) spectroscopy. The results demonstrate that at 220 oC for 24 h, the molar ratio of thiourea/Gd3+ has no significant impact on the phase composition of Gd2O2S products. With the reaction time increased from 6 h to 24 h, the morphology of Gd2O2S samples changed from ellipsoidal to near-spheroidal structure, but still remained hollow structure. PL results show that the strongest emission peaks for Gd2O2S:Eu3+ and Gd2O2S:Tb3+ samples were centered at 625 nm and 545 nm, corresponding to the 5D0→7F2 transition of Eu3+ ions and 5D4→7F5 transition of Tb3+ ions, respectively. The quenching concentrations for Eu3+ and Tb3+ ions were 12% and 6%, which can be attributed to the exchange interaction for Eu3+ and Tb3+ ions, respectively.

Preparation and Properties of CuInS2 Thin-Film by Successive Ionic Layer Adsorption and Reaction (SILAR) Method

2007 ◽  
Vol 280-283 ◽  
pp. 877-880
Author(s):  
Zheng Guo Jin ◽  
Yong Shi ◽  
Ji Jun Qiu ◽  
Xiao Xin Liu
Keyword(s):  
Thin Films ◽  
Absorption Spectrum ◽  
Optical Absorption ◽  
Optical Absorption Spectrum ◽  
Photoelectron Spectra ◽  
Molar Ratio ◽  
Silar Method ◽  
X Ray ◽  
Cuins2 Thin Films ◽  
Ionic Layer

CuInS2 thin films were deposited on galss substrate by successive ionic layer absorption and reaction (SILAR) method at room temperature. CuCl2, InCl3, and Na2S were used as precursor materials. The thin films were obtained during the dipping of 20-40 cycles and after annealing in the N2 atmosphere at 500°C. The characterization of the film was carried out by X-ray diffraction, scanning electron microscopy, optical absorption spectrum and X-ray photoelectron spectra. Quantification of the XPS peaks shows that the molar ratio of Cu:In:S of the film is close to the stoichiometry of CuInS2. XRD result demonstrated that the formed compound is CuInS2 with chalcopyrites crystal structure. Direct band gap was found to be 1.5eV from optical absorption spectrum.

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