Controlling the Properties of Bulk Metal Oxides at a Molecular Level: Alkoxides Vs Carboxylates‐Alkoxides Routes

1994 ◽  
Vol 346 ◽  
Author(s):  
Liliane G. Hubert‐pfalzgraf ◽  
Stephane Daniele ◽  
Souad Boulmaaz ◽  
Renee Papiernik
Keyword(s):  
Light Scattering ◽  
Metal Oxides ◽  
Single Crystals ◽  
Molecular Level ◽  
Bulk Metal ◽  
X Ray ◽  
Material Data ◽  
Metal Derivatives ◽  
Ft Ir ◽  
Insight Into

ABSTRACTThe reactions between alkoxides and/or alkoxides and anhydrous acetates have been investigated for access to advanced multicomponent niobates or titanates and with the aim to get insight into relationships between the nature of the initial precursors ‐ single or mixed‐metal derivatives, ligands (OAc or OR, R = Et, iPr),…‐ and the properties of the final material. Data are based on a variety of techniques: FT‐IR, multinuclear NMR (1H, 13C, 207Pb, 113Cd), X‐ray investigations on single crystals. Powders have been analyzed by TGA, SEM‐EDX, light scattering and XRD.

scholarly journals A facile method to fabricate AC/CuO for efficient removal of organic pollutants by adsorption and persulfate-based advanced oxidation processes

2020 ◽  
Author(s):  
Youlin Li ◽  
Yu Hu ◽  
Wenqiao You ◽  
Guangming Zhou ◽  
Guilong Peng
Keyword(s):  
Catalytic Performance ◽  
Catalytic Degradation ◽  
Maximum Adsorption Capacity ◽  
Efficient Removal ◽  
X Ray ◽  
One Step ◽  
Ft Ir ◽  
Degradation Reaction ◽  
The Relationship ◽  
Insight Into

Abstract Activated carbon/CuO (AC/CuO) composites was prepared through a facile one-step hydrothermal method and used as a bifunctional material for adsorption and catalysis degradation of bisphenol A (BPA). The composite was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray powder diffraction (XRD). The obtained AC/CuO exhibited excellent adsorption and catalytic performance. The maximum adsorption capacity of BPA on the AC/CuO was 319.03 mg/g according to the Langmuir fitting. At an initial BPA concentration of 20 mg/L, the BPA degradation efficiencies were maintained above 96% for 15 min by using 20 mg/L AC/CuO and 2 mM peroxymonosulfate (PMS). Moreover, the relationship between adsorption and catalytic degradation was also investigated. The results indicated that the pre-adsorption disfavored the degradation reaction. This work not only provides a novel preparation method for AC/CuO catalyst, but also gives a deeper insight into the mechanisms between adsorption and catalytic degradation.

scholarly journals Sulfonitric Treatment of Multiwalled Carbon Nanotubes and Their Dispersibility in Water

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2442 ◽  
Author(s):  
Hui Liu ◽  
Jianfeng Wang ◽  
Jiachen Wang ◽  
Suping Cui
Keyword(s):  
Carbon Nanotubes ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Oxidation Degree ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Scattering Measurements ◽  
Ft Ir

In this study, Multiwalled carbon nanotubes (MWCNTs) were oxidized by a mixture of sulfuric acid and nitric acid (V:V = 3:1) at 70 °C for 1, 2, and 4 h, respectively. The oxidized MWCNTs were characterized by N2 adsorption, Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), and Raman spectroscopy to determine the oxidation degree. The dispersion of the MWCNTs was investigated by UV-vis-NIR, SEM, and dynamic light scattering measurements. Results show that sulfonitric treatment increased the surface area and total pore volume and reduced the average pore diameter of MWCNTs. The treatment promoted the formation of oxidized species on the surface MWCNTs, as identified by FT-IR, TGA, and X-ray photoelectron spectroscopy measurements, and more oxygen-containing functional groups were generated when treatment time was extended. Moreover, a general relationship between oxidation degree and dispersibility of MWCNTs in water was established. UV-vis-NIR and dynamic light scattering measurements and SEM images revealed that MWCNTs with higher oxidation degree showed better dispersibility in water.

scholarly journals Growth and Characterization of Pure and Doped L-Alanine Tartrate Single Crystals

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
K. Rajesh ◽  
B. Milton Boaz ◽  
P. Praveen Kumar
Keyword(s):  
Single Crystals ◽  
Vickers Microhardness ◽  
Diffraction Method ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Single crystals of pure and Lanthanum doped L-Alanine Tartrate were grown by slow evaporation method. The cell parameters were determined using single crystal X-ray diffraction method. To improve the physical properties of the LAT crystal, Lanthanum dopant was added by 2 mol%. ICP studies confirm the presence of Lanthanum in the grown LAT crystal. Transparency range of the crystal was determined using UV-VIS-NIR spectrophotometer. The functional groups of pure and doped LAT crystals were analyzed by FT-IR spectroscopy. Using Vickers microhardness tester, mechanical strength of the material was found. Dielectric studies of pure and doped LAT single crystals were carried out. The doped LAT crystal is found to have efficiency higher than that of pure LAT crystal.

A study of the effect of annealing on Fe-doped LiNbO3by HRXRD, XRT and FT–IR

2005 ◽  
Vol 38 (5) ◽  
pp. 768-771 ◽  
Author(s):  
G. Bhagavannarayana ◽  
R. V. Ananthamurthy ◽  
G. C. Budakoti ◽  
B. Kumar ◽  
K. S. Bartwal
Keyword(s):  
Fourier Transform ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Elevated Temperatures ◽  
Annealing Effect ◽  
Molar Ratio ◽  
Structural Perfection ◽  
X Ray ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The annealing effect on the structural perfection of Fe-doped LiNbO3single crystals has been studied by high-resolution X-ray diffractometry (HRXRD), X-ray topography (XRT) and Fourier transform infrared (FT–IR) spectroscopy. The single crystals, prepared by mixing Li2CO3and Nb2O5powders in the molar ratio 48.6:51.4 with 0.05 mol% of iron at 1415 (1) K, were grown by the Czochralski (CZ) method along the [001] direction in air and poled during crystal growth by the application of a DC field. Two low-angle (tilt angle ∼1 arc minute) structural grain boundaries were observed in as-grown specimens. FT–IR spectra revealed that these crystals contain OH−and CO32−ionic defects. Grain boundaries and CO32−ionic defects were successfully removed, while the concentration of OH−ions was considerably reduced by post-growth thermal annealing at elevated temperatures.

Cl–OH ion-exchanging process in chlorapatite (Ca5(PO4)3Cl x (OH)1 − x ) – a deep insight

2012 ◽  
Vol 68 (5) ◽  
pp. 467-479 ◽  
Author(s):  
Esther García-Tuñón ◽  
Bruno Dacuña ◽  
Guillermo Zaragoza ◽  
Jaime Franco ◽  
Francisco Guitián
Keyword(s):  
Single Crystals ◽  
Point Of View ◽  
Molten Salt Method ◽  
Thermal Treatments ◽  
Ionic Exchange ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Fourier Transform Ir ◽  
Energetic Point

We have synthesized large chlorapatite [ClAp, Ca5(PO4)3Cl x (OH)1 − x , where x = 1] single crystals using the molten salt method. We have corroborated that the hexagonal symmetry P63/m describes the crystal structure best, even though the crystals are synthetic and stoichiometric. Moreover, we have performed several thermal treatments on these ClAp crystals, generating new single crystals in the apatite system [Ca5(PO4)3Cl x (OH)1 − x , where x ≤ 1], where the chloride anions (Cl−) were systematically substituted by hydroxyl anions (OH−). These new single crystals were methodically characterized by powder and single-crystal X-ray diffraction (SXRD), scanning electron microscopy (SEM), Fourier transform–IR spectroscopy (FT–IR), and energy-dispersive X-ray spectroscopy (EDS). We have discovered a previously unreported OH− inclusion site substituting the Cl− anion during the ion-exchanging process. Finally, we evaluated the atomic rearrangements of the other species involved in the structure. These movements are associated with ionic exchange, which can be justified from an energetic point of view. We also found a novel phase transformation at high temperature. When the crystals are heated over 1753 K the apatite system evolves to a less ordered monoclinic structure, in which the complete loss of the species in the anionic channel (Cl−, OH−) has been confirmed.

In-situ X-ray Studies of Clean Catalytic Technologies

2011 ◽  
Vol 1351 ◽  
Author(s):  
Adam F. Lee ◽  
Christine V. Ellis ◽  
Mark A. Newton ◽  
Christopher M. Parlett ◽  
Karen Wilson
Keyword(s):  
Rational Design ◽  
Heterogeneous Catalysts ◽  
Molecular Level ◽  
Aerobic Oxidation ◽  
Allylic Alcohols ◽  
Time Resolved ◽  
X Ray ◽  
Adsorbed Layers ◽  
Insight Into

ABSTRACTThe rational design of new heterogeneous catalysts for clean chemical technologies can be accelerated by molecular level insight into surface chemical processes. In-situ methodologies, able to provide time-resolved and/or pressure dependent information on the evolution of reacting adsorbed layers over catalytically relevant surfaces, are therefore of especial interest. Here we discuss the application of in-situ XPS and in-situ, synchronous DRIFTS/MS/XAS methodologies to elucidate the active site in Pd-catalyzed, selective aerobic oxidation of allylic alcohols.

SYNTHESIS OF NOVEL NANOSTRUCTURED LANTHANUM COBALT FERRITE MIXED METAL OXIDES BY SOL–GEL

2013 ◽  
Vol 12 (01) ◽  
pp. 1350007
Author(s):  
V. MARY TERESITA ◽  
V. JESEENTHARANI ◽  
B. AVILA JOSEPHINE ◽  
S. ARUL ANTONY
Keyword(s):  
Metal Oxides ◽  
Sol Gel ◽  
Chemical Properties ◽  
Mixed Metal Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mixed Metal ◽  
Size Dependent ◽  
Ft Ir ◽  
And Chemical Properties

Properties of nanoscale materials are very interesting and these are either comparable to or superior to those of bulk. These materials are interesting due to their exciting size dependent optical, electronic, magnetic, thermal, mechanical and chemical properties. Different mole ratios of nanostructured mixed metal oxides of LaCo x Fe 1-x O 3-δ (x = 0 to 1) were prepared by the sol–gel method by varying the mole ratios of iron and cobalt substrates. The compounds were sintered for 700°C in the tubular furnace for 8 h. The purity of the compounds was analyzed by TG-DTA. The compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) studies were employed to study the structural phases, vibrational frequencies, surface morphology of the highest humidity sensing compounds.

Scintillation of Un-doped ZnO Single Crystals

MRS Advances ◽  
2016 ◽  
Vol 1 (2) ◽  
pp. 121-126 ◽  
Author(s):  
A. M. Colosimo ◽  
Jianfeng Ji ◽  
P. S. Stepanov ◽  
L. A. Boatner ◽  
F. A. Selim
Keyword(s):  
Single Crystals ◽  
Photo Luminescence ◽  
Radiation Detectors ◽  
Scientific Instruments ◽  
Good Energy Resolution ◽  
X Ray ◽  
Good Energy ◽  
Anode Signal ◽  
Doped Zno ◽  
Insight Into

ABSTRACTScintillation properties are often studied by photo-luminescence (PL) and scintillation measurements. In this work, we combine X-ray-induced luminescence (XRIL) spectroscopy [Review of Scientific Instruments 83, 103112 (2012)] with PL and standard scintillation measurements to give insight into the scintillation properties of un-doped ZnO single crystals. XRIL revealed that ZnO luminescence proportionally increases with X-ray power and exhibits excellent linearity - indicating the possibility of developing radiation detectors with good energy resolution. By coupling ZnO crystals to fast photomultiplier tubes and monitoring the anode signal, rise times as fast as 0.9 ns were measured.

Correlating Infrared and X-ray Absorption Energies for Molecular-Level Insight into Hydrogen Bond Making and Breaking in Solution

2015 ◽  
Vol 119 (25) ◽  
pp. 8115-8124 ◽  
Author(s):  
Mirabelle Prémont-Schwarz ◽  
Simon Schreck ◽  
Marcella Iannuzzi ◽  
Erik T. J. Nibbering ◽  
Michael Odelius ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Molecular Level ◽  
X Ray ◽  
X Ray Absorption ◽  
Insight Into

Über neuere Polymetallate / Polyanions of Novel Structural Types

1973 ◽  
Vol 28 (7-8) ◽  
pp. 389-404 ◽  
Author(s):  
Joachim Fuchs
Keyword(s):  
Single Crystals ◽  
Vibrational Spectroscopy ◽  
Metal Salt ◽  
Organic Cations ◽  
Salt Solutions ◽  
X Ray ◽  
Structural Types ◽  
Insight Into ◽  
Complicated Mechanism

By the application of newer preparative methods and specific organic cations single crystals of polymetallates were obtained of till now unknown structural types. These are salts with polyanions W6O192-, W10O324-, [HW12O38(OH)2]5-, Mo6O192- and HV4O123-, furthermore para-tungstates A and B, as well as the compounds [N(CH)3)4]2 Μο8Ο25·5Η2Ο and [N(CH3)4]2Mo10 O31 · 7H2O. The structures of the anions W6O192- and W10O324- were elucidated by X-Ray analyses; the structure of the Μο6Ο192- was derived by vibrational spectroscopy. The knowledge of newer polyanion structures increasingly enables us to gain an insight into the complicated mechanism of oxyhydrate formation by acidification of metal salt solutions.

Sign in / Sign up

Export Citation Format

Share Document