Micro-Raman Spectroscopic Characterization of Nanosized TiO2 Powders Prepared by Vapor Hydrolysis

1998 ◽  
Vol 13 (9) ◽  
pp. 2602-2609 ◽  
Author(s):  
Yun-Hong Zhang ◽  
Chak K. Chan ◽  
John F. Porter ◽  
Wei Guo
Keyword(s):  
Spectroscopic Characterization ◽  
Spatial Inhomogeneity ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
Raman Analysis ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Hydrolysis Of ◽  
Nanosized Tio2

Micro-Raman analysis was used to study the structure of TiO2 powders produced at low (260 °C) and high (600–900 °C) temperatures by vapor hydrolysis of titanium tetraisopropoxide (TTIP). Spatial inhomogeneity was discovered after the amorphous TiO2 powders produced at low temperature were calcined at 700, 800, and 900 °C for 3 h. The TiO2 powders produced at high temperatures (from 600 to 900 °C) were found to be spatially homogeneous and predominately anatase in structure. Small amounts of rutile and brookite are found for powders produced at 700, 800, and 900 °C after calcination at 600 °C for 3 h. The rutile and brookite impurities are believed to be concentrated on the surface of anatase based on a comparison of results of Raman and x-ray diffraction studies.

scholarly journals Synthesis and Characterization of K-Ta Mixed Oxides for Hydrogen Generation in Photocatalysis

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Beata Zielińska ◽  
Ewa Mijowska ◽  
Ryszard J. Kalenczuk
Keyword(s):  
Diffuse Reflectance ◽  
Hydrogen Generation ◽  
Mixed Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Photocatalytic Hydrogen Generation ◽  
Irregular Structure ◽  
Transmission Electron

K-Ta mixed oxides photocatalysts have been prepared by impregnation followed by calcination. The influence of the reaction temperature (450°C–900°C) on the phase formation, crystal morphology, and photocatalytic activity in hydrogen generation of the produced materials was investigated. The detailed analysis has revealed that all products exhibit high crystallinity and irregular structure. Moreover, two different crystal structures of potassium tantalates such as KTaO3and K2Ta4O11were obtained. It was also found that the sample composed of KTaO3and traces of unreacted Ta2O5(annealed at 600°C) exhibits the highest activity in the reaction of photocatalytic hydrogen generation. The crystallographic phases, optical and vibronic properties were examined by X-ray diffraction (XRD) and diffuse reflectance (DR) UV-vis and resonance Raman spectroscopic methods, respectively. Morphology and chemical composition of the produced samples were studied using a high-resolution transmission electron microscope (HR-TEM) and an energy dispersive X-ray spectrometer (EDX) as its mode.

scholarly journals Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1498 ◽  
Author(s):  
Abdul Hafeez ◽  
Zareen Akhter ◽  
John F. Gallagher ◽  
Nawazish Ali Khan ◽  
Asghari Gul ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Spectroscopic Characterization ◽  
Spectroscopic Techniques ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Electrically Conductive ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Ft Ir

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.

Structural and IR-spectroscopic characterization of magnesium acesulfamate

2016 ◽  
Vol 71 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Oscar E. Piro ◽  
Gustavo A. Echeverría ◽  
Beatriz S. Parajón-Costa ◽  
Enrique J. Baran
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Elemental Analysis ◽  
Spectroscopic Characterization ◽  
Magnesium Carbonate ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Ir Spectroscopic

AbstractMagnesium acesulfamate, Mg(C4H4NO4S)2·6H2O, was prepared by the reaction of acesulfamic acid and magnesium carbonate in aqueous solution, and characterized by elemental analysis. Its crystal structure was determined by single crystal X-ray diffraction methods. The substance crystallizes in the triclinic space group P1̅ with one molecule per unit cell. The FTIR spectrum of the compound was also recorded and is briefly discussed. Some comparisons with other simple acesulfamate and saccharinate salts are also made.

Synthesis and Characterization of Tetrakis(pentafluoroethyl)germane

Synthesis ◽  
2017 ◽  
Vol 49 (11) ◽  
pp. 2389-2393 ◽  
Author(s):  
Stefanie Pelzer ◽  
Beate Neumann ◽  
Hans-Georg Stammler ◽  
Nikolai Ignat’ev ◽  
Reint Eujen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Diffraction Analysis ◽  
Spectroscopic Characterization ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Comprehensive Characterization

This paper describes the synthesis and comprehensive characterization of tetrakis(pentafluoroethyl)germane. In addition to a complete NMR spectroscopic characterization, including the rarely used 73Ge NMR spectroscopy, Ge(C2F5)4 was studied by IR spectroscopy, mass spectrometry as well as X-ray diffraction analysis. A 73Ge NMR investigation as well as an X-ray diffraction study of the related germane Ge(CF3)4 are also included.

Crystallographic and spectroscopic characterization of a natural Zn-rich spinel approaching the endmember gahnite (ZnAl2O4) composition

2013 ◽  
Vol 77 (7) ◽  
pp. 2941-2953 ◽  
Author(s):  
V. D’Ippolito ◽  
G. B. Andreozzi ◽  
F. Bosi ◽  
U. Hålenius ◽  
L. Mantovani ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Spectroscopic Characterization ◽  
Structural Formula ◽  
Unit Cell Dimension ◽  
X Ray Diffraction ◽  
Crystal Chemical Analysis ◽  
X Ray ◽  
Intervalence Charge Transfer ◽  
Oxide Spinel

AbstractThe crystal chemistry of a natural, gem-quality, blue-grey Zn-rich spinel crystal from Jemaa, Kaduna State, Nigeria, was studied using electron microprobe, single-crystal X-ray diffraction, optical absorption and Raman spectroscopies. The composition of the crystal approaches the gahnite endmember (ZnAl2O4), ∼94 mol.%, with the remainder being dominated by a hercynite component (FeAl2O4). The unit-cell dimension is 8.0850(3) Å and the tetrahedral and octahedral bond distances are determined as T–O 1.9485(6) Å and M–O 1.9137(3) Å. Crystal chemical analysis resulted in the empirical structural formula T(Zn0.94Fe2+0.03Al0.03)M (Al1.96Fe2+0.03Fe3+0.01)O4, which shows Zn and Al almost fully ordered in the tetrahedrally and octahedrally coordinated T and M sites, respectively. Raman spectra obtained using the excitation of the blue 473.1 nm line of a Nd:YAG laser display three of the five Raman-active modes predicted for the general oxide spinel group of minerals. These are the Eg mode at 420.6 cm–1 and the T2g modes at 510 cm–1 and 661 cm–1, due to vibrations in the AlO6 octahedra. Optical absorption spectra recorded in the UV/VIS-NIR-MIR range 2000 29000 cm–1 show a dominant absorption band at ∼5000 cm–1 which is caused by spin-allowed electronic d–d transitions in Fe2+ located at the T sites. The blue-grey hue exhibited by the sample is mainly due to spin-forbidden electronic transitions in TFe2+ and to MFe2+ ↔MFe3+ intervalence charge transfer, and the poor saturation of the colour is due to the small concentration of Fe2+ and Fe3+.

scholarly journals Characterization of FeOOH Nanoparticles and Amorphous Silica Matrix in an FeOOH-SiO2Nanocomposite

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Guido Ennas ◽  
Maria F. Casula ◽  
Sergio Marras ◽  
Gabriele Navarra ◽  
Alessandra Scano ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Amorphous Silica ◽  
Diffraction Data ◽  
Silica Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Matrix ◽  
Curve Method ◽  
Hydrolysis Of

A nanocomposite with an FeOOH/SiO2ratio equal to 17.7 wt% and the pertinent matrix, obtained by etching away the nanoparticles through reaction with hydrochloric acid, were investigated by XRD, TGA-DTA, heliostereopicnometry, BET, and TEM techniques. The study shows the presence in the nanocomposite of ferrihydrite nanoparticles phase with average dimensions around 4 nm. The FeOOH nanoparticles structure was analyzed by synchrotron X-ray diffraction data using the distribution difference curve method. The porous structure of the matrix resulting by etching away the nanoparticles differs significantly from that of a pureSiO2sample obtained by hydrolysis of TEOS under the same operative conditions followed in the nanocomposite preparation.

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