scholarly journals The effect of precursors salts on surface state of Pd/Al2O3 and Pd/CeO2/Al2O3 catalysts

2004 ◽  
Vol 76 (4) ◽  
pp. 825-832 ◽  
Author(s):  
André L. Guimarães ◽  
Lídia C. Dieguez ◽  
Martin Schmal
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Oxygen Storage ◽  
Promoting Effect ◽  
X Ray ◽  
Surface Active ◽  
Al2o3 Catalyst

The influence of the precursors on the promoting effect of ceria on Pd/Al2O3 catalyst, when ceria is coated over alumina was studied. The reaction of propane oxidation proceeded under different feed conditions and the surface active sites were characterized by X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance spectroscopy (DRS). XPS and DRS results show that PdO/Pd0 interface are the active sites independent of the precursor, while the catalysts containing CeO2 showed formation of palladium species in the highest oxidation state, probably PdO2 (338 eV) after the oxidation of propane. Besides, the O/Al and O/Ce ratios evidenced the increase of oxygen storage in the presence of CeO2. In addition, the precursor acetylacetonate favors the oxygen storage in the lattice.

scholarly journals The nature and effects of rhodium and antimony dopants on the electronic structure of TiO2: towards design of Z-scheme photocatalysts

2016 ◽  
Vol 4 (18) ◽  
pp. 6946-6954 ◽  
Author(s):  
E. N. K. Glover ◽  
S. G. Ellington ◽  
G. Sankar ◽  
R. G. Palgrave
Keyword(s):  
Fine Structure ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Edge Structure ◽  
X Ray ◽  
Antimony Doping ◽  
X Ray Absorption

The nature and effects of rhodium and antimony doping in TiO2 have been investigated using X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Extended X-ray Absorption Fine Structure (EXAFS), X-ray Absorption Near Edge Structure (XANES) and diffuse reflectance spectroscopy.

scholarly journals Design of Defect and Metallic Silver in Silver Phosphate Photocatalyst Using the Hydroxyapatite and Glucose

2020 ◽  
Vol 20 (6) ◽  
pp. 1441
Author(s):  
Uyi Sulaeman ◽  
Suhendar Suhendar ◽  
Hartiwi Diastuti ◽  
Roy Andreas ◽  
Shu Yin
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Glucose Solution ◽  
Reflectance Spectroscopy ◽  
Metallic Silver ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silver Phosphate ◽  
Agno3 Aqueous Solution

The defect and metallic silver (Ag) in silver phosphate (Ag3PO4) photocatalyst were successfully generated using hydroxyapatite (HA) and glucose. Two steps of synthesis were done in these experiments. Firstly, the Ag/HA powder was prepared by reacting AgNO3 and HA, followed by the addition of a glucose solution. Secondly, the suspension of Ag/HA was reacted with AgNO3 aqueous solution. The yellow product of Ag/Ag3PO4 photocatalyst was produced. The products were characterized using X-Ray Diffraction (XRD), Diffuse Reflectance Spectroscopy (DRS), Scanning Electron Microscope (SEM), Brunauer–Emmett–Teller (BET) and X-ray Photoelectron Spectroscopy (XPS). The decreased ratio of O/Ag and metallic Ag formation observed by the XPS was detected as the possible defect and Ag-doping in the photocatalyst. The enhanced photocatalytic activity might be caused by the oxygen vacancy and metallic Ag in Ag3PO4 that enables the separation of photo-generated electrons and holes.

Synthesis and Photocatalytic Activity of Fluorine DOPED-g-C3N4

2019 ◽  
Vol 889 ◽  
pp. 24-32 ◽  
Author(s):  
Nguyen Van Phuc ◽  
Doan Tran An ◽  
Nguyen Ngoc Tri ◽  
Tran Huu Ha ◽  
Tran Thi Thu Hien ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
Diffuse Reflectance ◽  
Dft Calculation ◽  
Diffuse Reflectance Spectroscopy ◽  
Weight Ratio ◽  
Ammonium Fluoride ◽  
X Ray Diffraction ◽  
Photo Degradation ◽  
X Ray

F-doped graphitic carbon nitride was synthesized via simple solid-state calcination of mixture with various weight ratios of urea, as precursor, and ammonium fluoride, as modifying agent. The obtained materials were characterized by a number of modern methods such as X-ray diffraction, Scanning electron microscopy, Infrared spectroscopy, Ultraviolet-visible diffuse reflectance spectroscopy, Thermo-gravimetry analysis, X-ray photoelectron spectroscopy, which all demonstrated the successful modification of g-C3N4 by fluorine. The experimental results illustrated that the doped sample, in which weight ratio of urea and ammonium fluoride equals 93:7 respectively, performs the highest photo-degradation efficiency of Rhodamine B up to 75 % after 7-hour visible light irradiation. The doping effect of fluorine on photo-catalytic activity of g-C3N4 was also discussed within supporting information of DFT calculation.

scholarly journals Preparation, Characterization, and Activity of Y2O3-ZnO Complex Oxides for the Photodegradation of 2,4-Dinitrophenol

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Tong-ming Su ◽  
Zu-zeng Qin ◽  
Hong-bing Ji ◽  
Yue-xiu Jiang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Complex Oxides ◽  
Reflectance Spectroscopy ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Adsorption Selectivity ◽  
X Ray ◽  
Strong Adsorption

With strong adsorption selectivity and thermal stability, Y2O3was added to ZnO to obtain Y2O3-ZnO complex oxides by a precipitation method. The Y2O3-ZnO complex oxides were characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, physisorption analyzer, and terephthalic acid photoluminescence probing techniques and were used for the degradation of 2,4-dinitrophenol. More hydroxyl radicals were generated on the surface of the ZnO after adding moderate Y2O3. The Y2O3-ZnO complex oxides which contained 0.50% Y2O3were proved to be the optimal photocatalyst and achieved a degradation of 81.2% of 2,4-dinitrophenol solution, compared to 57.6% achieved under the same photocatalytic conditions with ZnO alone.

scholarly journals Au/TiO2Reusable Photocatalysts for Dye Degradation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Silija Padikkaparambil ◽  
Binitha Narayanan ◽  
Zahira Yaakob ◽  
Suraja Viswanathan ◽  
Siti Masrinda Tasirin
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Pollutants ◽  
Transmission Electron ◽  
Uv Visible

Nanogold doped TiO2catalysts are synthesized, and their application in the photodegradation of dye pollutants is studied. The materials are characterized using different analytical techniques such as X-ray diffraction, transmission electron microscopy, UV-visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The results revealed the strong interaction between the metallic gold nanoparticles and the anatase TiO2support. Au doped systems showed very good photoactivity in the degradation of dye pollutants under UV irradiation as well as in sunlight. A simple mechanism is proposed for explaining the excellent photoactivity of the systems. The reusability studies of the photocatalysts exhibited more than 98% degradation of the dye even after 10 repeated cycles.

Preparation of BiXY(2-X)O3 and its Photocatalytic Degradation of Molasses Fermentation Wastewater under Visible-Light Irradiation

2011 ◽  
Vol 287-290 ◽  
pp. 1640-1645 ◽  
Author(s):  
Min Guang Fan ◽  
Zu Zeng Qin ◽  
Zi Li Liu ◽  
Tong Ming Su
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Active Oxygen Species ◽  
Light Irradiation ◽  
X Ray

A series of BixY(2-x)O3photocatalysts were successfully prepared by a solid-state reaction and were subsequently characterized by powder X-ray diffraction, UV-vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy (XPS). The UV-vis diffuse reflectance spectra revealed that the BixY(2-x)O3samples absorbed light in the visible-light range (400-800 nm). The XPS results indicated that active oxygen species were generated on the Bi1.8Y0.2O3surface, which displayed a higher photocatalytic activity. When using photocatalytic degradation molasses fermentation wastewater as a model reaction, the Bi1.8Y0.2O3showed higher photocatalytic activity in comparison to Bi0.2Y1.8O3under visible-light irradiation.

A Facile Synthesis of CuInS2 Nanoparticles from Molecular Single Source Precursors

2007 ◽  
Vol 7 (12) ◽  
pp. 4353-4364 ◽  
Author(s):  
Dimple P. Dutta ◽  
Garima Sharma ◽  
A. K. Tyagi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Optical Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Facile Synthesis ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron

CuInS2 nanoparticles have been synthesized via solvent thermolysis of novel bimetallic complexes of the general formula [(Ph3P)2 CuIn(S2COR)4] (where R = CH3; C2H5; C(CH3)2; and [(Ph3P)2 CuIn(SCH2CH2S)2]. These complexes have been prepared by the reactions of Na/KS2 COR and NaSCH2 CH2 SNa with InCl3 and [(Ph3 P)2 CuNO3] in methanol, respectively. Solvent thermolyses of these complexes were carried out in ethylene glycol at 196 °C for different time periods. The nanoparticles obtained were characterized extensively by techniques like powder X-ray diffraction, transmission electron microscopy, selected area electron diffraction, and X-ray photoelectron spectroscopy. The optical band gap of the nanoparticles was determined by diffuse reflectance spectroscopy (DRS).

scholarly journals Silver/Carbon Codoped Titanium Dioxide Photocatalyst for Improved Dye Degradation under Visible Light

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
P. Nyamukamba ◽  
L. Tichagwa ◽  
S. Mamphweli ◽  
L. Petrik
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Of

Herein, we report the synthesis of quartz supported TiO2 photocatalysts codoped with carbon and silver through the hydrolysis of titanium tetrachloride followed by calcination at 500°C. The prepared samples were characterized by UV-Vis diffuse reflectance spectroscopy, high resolution scanning electron microscopy (HRSEM), Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Codoping of TiO2 with Ag and carbon resulted in an increase in the surface area of the photocatalyst and altered the ratio of the anatase to rutile phase. The absorption edge of all the doped TiO2 photocatalysts redshifted and the band gap was reduced. The lowest band gap of 1.95 eV was achieved by doping with 0.5% Ag. Doping TiO2 using carbon as the only dopant resulted in a quartz supported photocatalyst that showed greater photocatalytic activity towards methyl orange than undoped TiO2 and also all codoped TiO2 photocatalysts under visible light irradiation.

In Situ X-ray Photoelectron Spectroscopy Detects Multiple Active Sites Involved in the Selective Anaerobic Oxidation of Methane in Copper-Exchanged Zeolites

ACS Catalysis ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 6728-6737 ◽  
Author(s):  
Luca Artiglia ◽  
Vitaly L. Sushkevich ◽  
Dennis Palagin ◽  
Amy J. Knorpp ◽  
Kanak Roy ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
X Ray ◽  
Oxidation Of Methane

Role Of Surface Defects In Metal-Ceramic Bonding

1991 ◽  
Vol 238 ◽  
Author(s):  
S. M. Mukhopadhyay ◽  
C. S. Chen
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Surface Defects ◽  
Second Phase ◽  
Interfacial Chemistry ◽  
X Ray ◽  
Thin Oxide Film ◽  
Metal Ceramic

ABSTRACTThe interfacial chemistry between Ni and Al2O3 has been studied during the initial stages of bonding. We have evaporated thin films of Ni on different alumina substrates (thin oxide film on metallic Al, polished and scratched sapphire crystals, surface with second phase precipitates) and have analyzed how the interface grows, in situ, using X-ray Photoelectron Spectroscopy. It was found that a certain fraction of the first monolayer of Ni which forms on the alumina surface undergoes charge transfer to form NiO. This is due to oxygen-active sites such as unattached oxygen bonds on the surface. A measure of the concentration of such sites can therefore be obtained from the submonolayer fraction of Ni that gets oxidized. It was found that a rough surface offered less oxidation sites for Ni than a smooth one whereas a surface with second phase MgAI2O4 (spinel) precipitates offered more oxidation sites. Also, there is much less oxidation on a thin film of amorphous alumina grown on metallic Al than on a polished bulk sapphire surface. The implications of these studies to further understanding of the metal-ceramic interface have been discussed.

Sign in / Sign up

Export Citation Format

Share Document