Study of the active sites of alkaline-earth Y-type zeolites by IR spectroscopy

1978 ◽  
Vol 13 (5) ◽  
pp. 541-544
Author(s):  
L. V. Levshin ◽  
L. A. Ignat'eva ◽  
L. V. Efimenko ◽  
G. D. Chukin ◽  
M. A. Piontkovskaya ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Active Sites ◽  
Alkaline Earth

scholarly journals Investigation of alkali and alkaline earth solvation structures in tetraglyme solvent

2021 ◽  
Author(s):  
L. H. B. Nguyen ◽  
T. Picard ◽  
N. Sergent ◽  
C. Raynaud ◽  
J.-S. Filhol ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Dft Calculations ◽  
Metal Ions ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Alkaline Earth Metal Ions

Solvation structures of alkali and alkaline earth metal ions in tetraglyme solvent were investigated by DFT calculations and IR spectroscopy.

Alkaline Earth Metal Oxide Nanocluster Modification of Rutile TiO2 (110) Promotes Water Activation and CO2 Chemisorption

2018 ◽  
Author(s):  
Michael Nolan
Keyword(s):  
Metal Oxide ◽  
Visible Light ◽  
Light Absorption ◽  
Environmental Remediation ◽  
Active Sites ◽  
Density Functional ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Alkaline Earth Oxide

Metal oxide photocatalysts are widely studied for applications in solar driven environmental remediation, antimicrobial activity, hydrogen production and CO<sub>2</sub> reduction to fuels. Common requirements for each technology include absorption of visible light, reduced charge carrier recombination and the ability to activate the initial molecule be it a pollutant, water or CO<sub>2</sub>. The leading photocatalyst is some form of TiO<sub>2</sub>. A significant amount of work has been undertaken to modifying TiO<sub>2</sub> to induce visible light absorption. The structure and composition of the catalyst should facilitate separation of electrons and holes and having active sites on the catalyst is important to promote the initial adsorption and activation of molecules of interest. In this paper we present a first principles density functional theory (DFT) study of the modification of rutile TiO<sub>2</sub> (110) with nanoclusters of the alkaline earth metal oxides (MgO, Ca, BaO) and we focus on the effect of surface modification on the key catalyst properties. The modification of rutile TiO<sub>2</sub> with CaO and BaO induces a predicted red shift in light absorption. In all cases, photoexcited electrons and holes localise on oxygen in the nanocluster and surface Ti sites, thus enhancing charge separation. The presence of these non-bulk alkaline earth oxide nanoclusters provides highly active sites for water and CO<sub>2</sub> adsorption. On MgO-rutile, water adsorbs molecularly and overcomes a barrier of only 0.36 eV for dissociation whereby hydroxyls are stabilised. On CaO- and BaO-modified rutile water adsorbs dissociatively. We attribute this to the high lying O 2p states in the alkaline earth oxide modifiers which are available to interact with water, as well as the non-bulk like geometry around the active site. Upon adsorption of CO<sub>2</sub> the preferred binding mode is as a tridentate carbonate-like species, as characterised by geometry and vibrational modes. The carbonate is bound by up to 4 eV. Thus these heterostructures can be interesting for CO<sub>2</sub> capture, helping alleviate the problem of CO<sub>2</sub> emissions.

On the nature of active sites and catalytic activity for OCM reaction of alkaline-earth oxides-neodymia catalytic systems

2010 ◽  
Vol 375 (1) ◽  
pp. 172-178 ◽  
Author(s):  
Florica Papa ◽  
Dana Gingasu ◽  
Luminita Patron ◽  
Akane Miyazaki ◽  
Ioan Balint
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Alkaline Earth ◽  
Catalytic Systems

scholarly journals Effect of doping TiO2 with alkaline-earth metal ions on its photocatalytic activity

2007 ◽  
Vol 72 (4) ◽  
pp. 393-402 ◽  
Author(s):  
Yuexiang Li ◽  
Shaoqin Peng ◽  
Fengyi Jiang ◽  
Gongxuan Lu ◽  
Shuben Li
Keyword(s):  
Photocatalytic Activity ◽  
Ir Spectroscopy ◽  
Metal Ions ◽  
Calcination Temperature ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Tio2 Photocatalysts ◽  
Alkaline Earth Metal Ions ◽  
Production Of Hydrogen

TiO2 photocatalysts doped with alkaline-earth metal ions were prepared by the impregnation and coprecipitation methods. The sample were characterized by XRD, XPS and IR spectroscopy. Their activities were evaluated by the photocatalytic production of hydrogen. The activities of the doped photocatalysts dopended on the size of the dopant ions and the doping method. The optimum molar contents of dopant ions Be2+, Mg2+, Ca2+, Sr2+, Ba2+ were 1.25, 1.25, 2.25, 2.25 and 2.25 at. %, respectively. The optimum calcination temperature and time were 400?C and 1 h. .

Characterization of an alkaline earth metal-doped solid superacid and its activity for the esterification of oleic acid with methanol

2015 ◽  
Vol 17 (6) ◽  
pp. 3609-3620 ◽  
Author(s):  
Chien-Chang Huang ◽  
Chieh-Ju Yang ◽  
Pei-Jyuan Gao ◽  
Nai-Ci Wang ◽  
Ching-Lung Chen ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Active Sites ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Schematic Diagram ◽  
Solid Superacid ◽  
Metal Doped ◽  
Barrier Zone

A schematic diagram for explaining the deactivation of the active sites located in the high diffusion barrier zone is shown.

Synthesis and characterization of a novel layered titanium phosphate

1996 ◽  
Vol 11 (10) ◽  
pp. 2490-2498 ◽  
Author(s):  
Anatoly I. Bortun ◽  
Lyudmila Bortun ◽  
Abraham Clearfield ◽  
María A. Villa-García ◽  
José R. García ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Acid Solution ◽  
Alkaline Earth ◽  
Transition Metal Ions ◽  
Phosphoric Acid Solution ◽  
Titanium Phosphate ◽  
Synthesis And Characterization ◽  
The Novel ◽  
X Ray

A novel metastable layered titanium phosphate has been synthesized by the treatment of layered titanates (Na2Ti3O7 and Na4Ti9O20) with 1–2 M phosphoric acid solution at 120–150 °C. Based on the data of 31P MAS NMR and IR spectroscopy, x-ray powder diffraction, and thermal and elemental analysis, the formula Ti2O3(H2PO4)2 · 2H2O was assigned to the novel compound. The layered nature of the compound was confirmed from n-alkylamine intercalation and the ion exchange behavior toward alkali, alkaline earth, and some transition metal ions.

scholarly journals WASTE ENGINE OIL REGENERATION WITH BENTONITE FROM THE NAVBAHOR DEPOSIT

2020 ◽  
Vol 2020 (3) ◽  
pp. 50-55
Keyword(s):  
Ir Spectroscopy ◽  
Alkaline Earth ◽  
Engine Oil ◽  
Optimal Conditions ◽  
Waste Oil ◽  
Secondary Products ◽  
Used Engine Oil ◽  
Waste Engine Oil ◽  
Main Components

The aim of the study was the regeneration of used oils. The change in the conditions for the regeneration of used engine oil as a result of adsorptive cleaning with alkaline earth clay from the Navbakhor deposit has been studied. The carried-out regeneration allows almost completely removing mechanical impurities, moisture from the waste oil and helps to clarify it. The optimal conditions for regeneration have been established. The removal of secondary products formed during the use of engine oil while retaining the main components that determine the serviceability of the product has been established. By means of IR spectroscopy, as a result, the possibility of using clay from the Navbakhor deposit for adsorption purification of used engine oil was determined.

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