Preparation and Characterization of TiO2 Nanostructures for Catalytic CO2 Photoconversion

2011 ◽  
Vol 183 ◽  
pp. 89-94 ◽  
Author(s):  
Anna Iwulska ◽  
G. Sliwinski
Keyword(s):  
Active Surface ◽  
Laser Pulses ◽  
Point Of View ◽  
Deep Penetration ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Content Ratio ◽  
Photocatalytic Applications

The titanium dioxide target (99.7%) of 1 cm in dia was ablated in vacuum by laser pulses (6 ns) at 266 nm and at repetition rate of 10 Hz. During deposition the laser fluence between 1 and 3.5 J/cm2 and the O2 pressure from the range of 10-2 – 1 Pa were applied. The thin TiO2 films were deposited on glass substrate (1 × 1 cm2) heated up to 500 °C. The chemical composition of the film and samples produced by annealing were investigated by spectroscopic techniques (μ-Raman, EDX) and the structure, porosity and surface morphology were analysed by means of SEM and x-ray diffraction (XRD). The SEM inspection of the TiO2 thin film samples indicates that the obtained material is mostly crystalline. After annealing in O2 at 500 °C the structure characterized by the presence of both anatase and rutile phases is observed in the Raman spectra and confirmed by the XRD data. The phase content ratio depends on the O2 pressure applied. Results confirm that nanostructures produced in this way represent densely packed columns and promote deep penetration of guest particles such as CO2.The resulting large active surface is advantageous from the point of view of photocatalytic applications.

X-ray Diffraction Studies of Polycrystalline Thin Films Using Glancing Angle Diffractometry

1988 ◽  
Vol 32 ◽  
pp. 311-321 ◽  
Author(s):  
R.A. Larsen ◽  
T.F. McNulty ◽  
R.P. Goehner ◽  
K.R. Crystal
Keyword(s):  
Thin Films ◽  
Deep Penetration ◽  
X Ray Diffraction ◽  
Parallel Beam ◽  
X Ray ◽  
Beam Geometry ◽  
Polycrystalline Thin Films ◽  
Glancing Angle ◽  
Parallel Beam Geometry

AbstractThe use of conventional θ/2θ diffraction methods for the characterization of polycrystalline thin films is not in general a satisfactory technique due to the relatively deep penetration of x-ray photons in most materials. Glancing incidence diffraction (GID) can compensate for the penetration problems inherent in the θ/2θ geometry. Parallel beam geometry has been developed in conjunction with GID to eliminate the focusing aberrations encountered when performing these types of measurements. During the past yearwe developed a parallel beam attachment which we have successfully configured to a number of systems.

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.

Synthesis and characterization of novel poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive

2020 ◽  
Vol 98 (12) ◽  
pp. 755-763
Author(s):  
Hamid Reza Ghayeni ◽  
Reza Razeghi ◽  
Abolfazl Olyaei
Keyword(s):  
Uv Light ◽  
Light Exposure ◽  
Sodium Acrylate ◽  
Spectroscopic Techniques ◽  
Effective Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cds Nanorods ◽  
Transmission Electron

Cadmium sulfide nanorods with a length of 69 nm have been prepared by using Cd(OAc)2.2H2O and S8 at 125 °C in the presence of triethylenetetramine as the template agent and coordination agent and characterized by using X-ray diffraction, transmission electron microscopy, FTIR, photoluminescence, and UV–vis absorption spectroscopic techniques. Photocopolymerization of glycidyl methacrylate (GMA) and sodium acrylate (SA) was carried out using CdS nanorods as a photocatalyst under UV light exposure at 400 nm in the presence of β-cyclodextrin (β-CD). To optimization of the effective parameters on the synthesis of copolymer nanocomposite, the amounts of initiator, monomers, and β-CD, duration of pre-deoxygenation, and light wavelength were evaluated. Ring opening of poly(GMA-co-SA)/CdS nanocomposite with NaN3 afforded poly(HAzPMA-co-SA)/CdS nanocomposite and subsequent mixing with RDX in DMF led to the formation of poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive. All of the copolymer nanocomposites were characterized using various tools of instrumental analysis.

scholarly journals Characterization of CuO thin films for gas sensing applications

2019 ◽  
Vol 14 (31) ◽  
pp. 1-12
Author(s):  
Jamal M. Rzaij
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Cupric Oxide ◽  
Laser Pulses ◽  
X Ray Diffraction ◽  
Energy Increase ◽  
Nano Structure ◽  
X Ray ◽  
Sensing Applications

Nanostructural cupric oxide (CuO) films were prepared on Si and glass substrate by pulsed laser deposition technique (PLD) using laser Nd:YAG, using different laser pulses energies from 200 to 600 mJ. The X-ray diffraction pattern (XRD) of the films showed a polycrystalline structure with a monoclinic symmetry and preferred orientation toward (111) plane with nano structure. The crystallite size was increasing with increasing of laser pulse energy. Optical properties was characterized by using UV–vis spectrometer in the wave lengthrange (200-1100) nm at room temperature. The results showed that the transmission spectrum decreases with the laser pulses energy increase. Sensitivity of NO2 gas at different operating temperatures, (50°C, 100°C, 150°C and 200°C) was calculated.

Molecular and X-ray Spectroscopies for Noninvasive Characterization of Mayan Green Stones from Bonampak, Chiapas

2019 ◽  
Vol 73 (9) ◽  
pp. 1074-1086
Author(s):  
Valentina Aguilar-Melo ◽  
Alejandro Mitrani ◽  
Edgar Casanova-Gonzalez ◽  
Mayra D. Manrique-Ortega ◽  
Griselda Pérez-Ireta ◽  
...  
Keyword(s):  
Archaeological Site ◽  
Molecular Techniques ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Noninvasive Characterization ◽  
A Minor

A burial and a rich offering were found under Room 2 in the Murals Building, Bonampak, a Mayan archaeological site situated in Chiapas, Mexico. This burial may be related with the creation of the famous mural paintings. A rich set of jewelry made of green stones was among the different objects found. Green stones have great importance in Mesoamerican cultures, those composed of jadeite being the most appreciated. To characterize the green stones, different spectroscopic techniques were used in a complementary way: Raman and infrared spectroscopies (FT-IR) were used for global mineralogical analysis, while X-ray diffraction (XRD) and X-ray fluorescence (XRF) were applied simultaneously in situ on the artifacts that were not successfully identified by these molecular techniques. In addition, XRF was used to contrasts the elemental information from pieces composed of pyroxenes that may be related to the raw sources of jade in Guatemala. The main minerals identified within the beads and earrings were jadeite with omphacite and jadeite with albite; to a minor extent, quartz, and serpentine. In this paper, the main features of the molecular and X-ray techniques are compared in order to determine the advantages and limitations of these spectroscopies for mineral identification. With this combination of techniques, it was possible to undertake a suitable characterization of the analyzed objects. This paper focuses on the XRD–XRF combined analysis for in situ noninvasive characterization.

scholarly journals STRUCTURAL CHARACTERIZATION OF 2-AMINO-2-OXOACETIC ACID BY X-RAY POWDER DIFFRACTION AND QUANTUM CHEMISTRY

2019 ◽  
Vol 16 (33) ◽  
pp. 516-523
Author(s):  
G. E. DELGADO ◽  
L. M. BELANDRIA ◽  
M. GUILLEN ◽  
A.. J. MORA ◽  
L. E. SEIJAS
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystal ◽  
Structural Study ◽  
Powder Diffraction ◽  
Structural Characterization ◽  
Structure Determination ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray

2-amino-2-oxoacetic acid, carbamoyl formic acid, or oxamic acid is an active pharmaceutical ingredient (API) of great importance mainly because is an inhibitor of lactic dehydrogenase (LDH). It acts as an inhibitor to the metabolic pathways of the tumor cells and exhibited significant anticancer activity against nasopharyngeal carcinoma (NPC) cells in vitro and can be considered as a potential drug for the treatment of type 2 diabetes. Also, this compound could be used as a building block in the design of supramolecular architectures based on hydrogen bonds through the complimentary hydrogen-bond functionalities of the carbonyl and amide functional groups present. Single-crystal X-ray diffraction is the most powerful technique for crystal structure determination of small molecules. However, for several materials, including oxamic acid, it could be complicated to grow single crystals of suitable size and quality that make them appropriated to structure analysis. For this reason, the structural study was conducted with powder X-ray diffraction which is a process significantly more challenging than structure determination from single-crystal data. Oxamic acid has been characterized by FT-IR and NMR spectroscopic techniques, thermal TGA-DSC analysis, semi-empirical PM7 calculations, and X-ray powder diffraction. The title compound crystallizes in the monoclinic system with space group Cc, Z=4, and unit cell parameters a= 9.4994(4) Å, b= 5.4380(2) Å, c= 6.8636(3) Å, b= 107.149(2)°, V= 338.79(2) Å3. The molecule has a trans conformation. The molecular structure and crystal packing are stabilized mainly by intra- and intermolecular O--H···O and N--H···O hydrogen bonds. The structural characterization of this type of API compound is important to understand its mechanisms of action due to its considerable biological effects. In particular, for oxamic acid, this structural study would allow subsequent examination of its medicinal properties as an antitumor and antidiabetic agent.

scholarly journals Synthesis and structural analysis of polynuclear silver(I) complexes with 4,7-phenanthroline

2019 ◽  
Vol 84 (7) ◽  
pp. 689-699 ◽  
Author(s):  
Ivana Stanojevic ◽  
Nada Savic ◽  
Aurélien Crochet ◽  
Katharina Fromm ◽  
Milos Djuran ◽  
...  
Keyword(s):  
Solid State ◽  
Room Temperature ◽  
Volume Ratio ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bridging Ligand ◽  
Coordination Sites ◽  
Hydrolysis Of

New polynuclear silver(I) complexes, [Ag(CF3SO3)(4,7-phen)(CH3CN)]n (1) and [Ag(PO2F2)(4,7-phen)]n (2), were synthesized by the reaction of 4,7-phenanthroline (4,7-phen) and the corresponding AgX salt (X = CF3SO3 - and PF6 -) in 1:2 mole ratio, respectively, in methanol/acetone (1:1 volume ratio) at room temperature. The characterization of the complexes was established on the basis of elemental microanalysis, IR and NMR (1H and 13C) spectroscopic techniques, while their crystal structures were determined by single-crystal X-ray diffraction analysis. The results of spectroscopic and crystallographic analyses revealed that in these complexes, 4,7-phen behaves as a bridging ligand between two metal ions, while the remaining coordination sites of the Ag(I) ions are occupied by the oxygen atom of CF3SO3 - and an acetonitrile nitrogen atom in 1 or by two oxygen atoms from two PO2F2 -, formed after hydrolysis of PF6 -, in 2. In the solid state, both complexes are coordination polymers in which the geometry around the Ag(I) ions is distorted tetrahedral.

scholarly journals Spectroscopic Characterization of Eoholocene Bones Found in a Cave in Northeast Brazil

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
P. V. Oliveira ◽  
M. S. S. Viana ◽  
O. A. Barros ◽  
P. T. C. Freire ◽  
F. I. Bezerra ◽  
...  
Keyword(s):  
National Park ◽  
Animal Species ◽  
Spectroscopic Characterization ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Future Studies ◽  
X Ray ◽  
Inorganic Chemical ◽  
Supply Information

The preservation of fossils depends on several interactions of organic and inorganic chemical processes. The hard parts, which are more suitable for fossilization, might record valuable information of biogenic processes, while the taphonomic characteristics supply information on postmortem chemical transformation. Here, X-ray fluorescence, X-ray diffraction, and infrared spectroscopy analyses were carried out in Early Eoholocene fragments of bones collected from the subsurface at Gruta do Urso Fóssil, Ubajara National Park, northeast of Ceará State in Brazil. It is suggested a lower degree of decomposition, a preservation of the original mineral composition, along with some incidence of encrustation, and the occurrence of different animal species are analyzed. These preliminary data serve as a basis for future studies involving fossil biota from the deposits of Gruta do Urso Fóssil using spectroscopic techniques.

E/Z Isomerization of 3-Hydrazonocamphor Promoted by Coordination to Palladium or Platinum

2007 ◽  
Vol 72 (5-6) ◽  
pp. 649-665 ◽  
Author(s):  
M. Fernanda N. N. Carvalho ◽  
Ana S. D. Ferreira ◽  
João L. Ferreira da Silva ◽  
Luís F. Veiros
Keyword(s):  
Free Ligand ◽  
Intramolecular Hydrogen Bonding ◽  
Planar Geometry ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Intramolecular Hydrogen ◽  
C Nmr

3-Hydrazonocamphor, 3-(RR1NN)C10H14O (R = Me, R1 = H), undergoes intramolecular hydrogen bridging by coordination to platinum or palladium. This effect is evidenced by considerable decrease in the ν(C=O) frequency (compared to the free ligand) in the IR spectra of the complexes [MCl2L2] (M = Pd, Pt; L = 3-(RR1NN)C10H14O) as well as by the magnetic non- equivalence of the two ligands, as revealed by 13C NMR. DFT calculations indicate that coordination of 3-(Me(H)NN)C10H14O promotes E/Z isomerization of the hydrazono group of the ligand, inducing formation of intramolecular hydrogen bonding and corresponding stabilization of the complex. Characterization of the complexes [MCl2L2] (M = Pt; L: R, R1 = Me (1), R = Me, R1 = H (2) and M = Pd; L: R = Me, R1 = H (3)) was performed by analytical and spectroscopic techniques. Redox properties of the 3-hydazonocamphors and their complexes were studied by cyclic voltammetry. The structure of trans-[PtCl2{3-(Me2NN)C10H14O}2] was determined by single-crystal X-ray diffraction analysis. The complex has square-planar geometry and crystallizes in the tetragonal P43 space group.

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