scholarly journals Textural properties of V2O5/TiO2 catalysts obtained from VOCl3

1985 ◽  
Vol 2 (4) ◽  
pp. 241-251 ◽  
Author(s):  
C. Martin ◽  
V. Rives
Keyword(s):  
Specific Surface ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Monolayer Coverage

V2O5/TiO2 systems have been obtained by reacting TiO2 (P-25 from Degussa, ca 55% anatase, or a rutilised modification, ca 3% anatase) with gaseous VOCl3. The samples have been characterised by X-ray diffraction, UV–Vis spectrophotometry and nitrogen adsorption at 77 K. For the anatase carrier, a monolayer coverage of V2O5 is achieved, but only 0·46 monolayers are formed with the rutilised support. The specific surface areas decrease upon incorporation of V2O5, and that seems to be well dispersed without forming crystallites.

Structural and surface aspects of thermally treated copper aluminium mixed hydroxides

1991 ◽  
Vol 69 (10) ◽  
pp. 1511-1515 ◽  
Author(s):  
Awad I. Ahmed ◽  
S. E. Samra ◽  
S. A. El-Hakam
Keyword(s):  
Pore Structure ◽  
Copper Content ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Structure Surface ◽  
Adsorption Desorption

CuO–Al2O3 catalysts containing various amounts of copper oxide have been prepared by precipitation. The phase changes were studied by X-ray diffraction. The results obtained revealed that the thermal treatment of solid CuO–Al2O3 at 700 °C produced only crystalline CuO. Heating to 900 °C led to the formation of copper alumina spinel together with unreacted CuO and γ-Al2O3. The spinel content was found to increase with increasing copper content. Nitrogen adsorption–desorption isotherms on the calcined samples have been measured. Surface areas have been calculated and the pore structure analysed. The textural properties of the system were found to depend on both the copper content and the calcination temperature. Key words: CuO, Al2O3 catalysts, structure, surface area, pore structure.

Study of the catalytic activity of Al-Fe pillared clays in the Baeyer–Villiger oxidation

Clay Minerals ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. 275-284 ◽  
Author(s):  
L. S. Belaroui ◽  
A. Bengueddach
Keyword(s):  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Pillared Clays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dissolved Iron ◽  
Surface Areas ◽  
Accessible Surface ◽  
Adsorption Desorption ◽  
Villiger Oxidation

AbstractThree types of AlFePILCs pillared clays have been prepared from Algerian clay precursors. They have been characterized and tested in the Baeyer–Villiger oxidation of cyclohexanone to caprolactone using benzaldehyde and oxygen as oxidant at room temperature. The structural and textural properties of the catalyst have been determined by X-ray diffraction, nitrogen adsorption-desorption isotherms and Mössbauer spectroscopy.The different activities of the clays have been related to their Fe contents and accessible surface areas. The induction period observed before the reaction started has been attributed to the dissolution of a portion of the Fe3+ cations, mediated by either the perbenzoic acid intermediate or the benzoic acid co-product. The reaction was indeed catalysed by a few ppm of dissolved iron cations and the catalysis of the Baeyer–Villiger oxidation reaction should mechanistically be considered as homogeneous.

SO2 adsorption on acid-treated bentonites from Turkey

Clay Minerals ◽  
2011 ◽  
Vol 46 (1) ◽  
pp. 73-83 ◽  
Author(s):  
M. Sakizci ◽  
B. Erdoğan Alver ◽  
E. Yörükoğullari
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Sulphur Dioxide ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Adsorption Capacities ◽  
So2 Adsorption ◽  
Specific Surface Areas

AbstractThe adsorption of sulphur dioxide (SO2) on two bentonites from Unye, Turkey (Kavaktepe and Yemişlitepe deposits – denoted below as BK and BY) and on forms treated with 1 and 2 M HCl solutions was investigated. The bentonite samples were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), thermogravimetry (TG-DTG), differential thermal analysis (DTA) and nitrogen adsorption methods. Adsorption capacities of SO2 were obtained using a standard volumetric apparatus at 293 K and 106 kPa. The SO2 adsorption capacity of the BY-2 (1.263 mmol g–1) sample was much greater than the BK-2 (1.126 mmol g–1) sample. As the concentration of acid increased, the specific surface areas and the uptakes of SO2 gas increased.

Synthesis of La0.8 Sr0.2 MnO3±δ Powders by Amorphous Citrate and Pechini Techniques

2005 ◽  
Vol 498-499 ◽  
pp. 630-635 ◽  
Author(s):  
Márcia Caldeira Brant ◽  
Jarlys Arthuri Zani ◽  
Fernando Soares Lameiras
Keyword(s):  
Specific Surface ◽  
Fluorescence Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Type Process ◽  
Complex Process ◽  
Structure Phase ◽  
Specific Surface Areas

La0.8Sr0.2MnO3±d (LSM) powders were prepared by a Pechini-type polymerizable complex process and by amorphous citrate technique. Both processes involve the complexation of the LSM cations from their nitrates or carbonates. The aim of this work is to determinate the differences between the powers obtained by these techniques. The powders synthesized by the Pechini-type process were calcined between 500 °C and 1100 °C. The powders prepared by amorphous citrate technique were calcined at 900 °C. No contamination of either of the powders was observed by X ray fluorescence analysis. X ray diffraction results showed that a perovskitetype structure phase was obtained. BET results showed that the specific surface areas of the powders prepared by the polymerizable complex process and the amorphous citrate route were 6.6 m2g-1 and 5.7 m2g-1, respectively.

scholarly journals Preparation Method of Co3O4Nanoparticles Using Degreasing Cotton and Their Electrochemical Performances in Supercapacitors

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Hongyan Xu ◽  
Libo Gao ◽  
Qiang Zhang ◽  
Junyang Li ◽  
Jiangtao Diwu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Adsorption ◽  
Electrochemical Performances ◽  
X Ray ◽  
Surface Areas ◽  
Synthetic Strategy ◽  
Different Temperatures ◽  
Specific Surface Areas

Co3O4nanoparticles were fabricated by a novel, facile, and environment-friendly carbon-assisted method using degreasing cotton. Structural and morphological characterizations were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The component of the sample obtained at different temperatures was measured by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Nitrogen adsorption and desorption isotherms were utilized to reveal the specific surface areas. The formation mechanism of Co3O4nanoparticles was also proposed, demonstrating that the additive degreasing cotton played an indispensable role in the process of synthesizing the sample. The resultant Co3O4sample calcined at 600°C exhibited superior electrochemical performance with better specific capacitance and long-term cycling life, due to its high specific surface areas and pores structures. Additionally, it has been proved that this facile synthetic strategy can be extended to produce other metal oxide materials (e.g., Fe3O4). As a consequence, the carbon-assisted method using degreasing cotton accompanied a promising prospect for practical application.

scholarly journals Study of sepiolite from Goles (Kosovo, Yugoslavia). II. Acid activation

2002 ◽  
Vol 67 (7) ◽  
pp. 499-506 ◽  
Author(s):  
Marina Radojevic ◽  
Vidojko Jovic ◽  
Dragomir Karaulic ◽  
Dragomir Vitorovic
Keyword(s):  
Specific Surface ◽  
Chemical Treatment ◽  
Acid Treatment ◽  
Nitrogen Adsorption ◽  
Adsorption Properties ◽  
Acid Activation ◽  
Surface Areas ◽  
Bet Method ◽  
Specific Surface Areas ◽  
Enhanced Adsorption

The changes in the pore structure and adsorption properties of sepiolite from Goles resulting from treatment with 4MHCl for various periods of time were investigated. The BET method specific surface areas, pore volumes and f ? plots were determined by nitrogen adsorption. The surface area progressively increased during the 70 hours of acid treatment, when a maximum was attained. The differences in the adsorption properties of the original and the acid treated sepiolite were evaluated by comparison of adsorption isotherms obtained with benzene, n-hexane, methanol and isooctane. The enhanced adsorption of isooctane was of great interest, since the sorption of this compound on natural sepiolites is generally very limited. The results suggest that chemical treatment of sepiolite with 4MHCl for 70 h produces an adsorbent of optimal porosity and other adsorption properties.

Investigation on Jurassic Shale Gas Reservoir Characteristics from Northern Qaidam Basin

2017 ◽  
Vol 748 ◽  
pp. 441-445
Author(s):  
Gui Xi Xu ◽  
Shu Zhong Wang ◽  
Xiang Rong Luo ◽  
Ze Feng Jing
Keyword(s):  
Mineral Content ◽  
Qaidam Basin ◽  
Nitrogen Adsorption ◽  
Test Results ◽  
X Ray Diffraction ◽  
Gas Reservoir ◽  
Average Pore ◽  
X Ray ◽  
Shale Gas Reservoir ◽  
Surface Areas

The Jurassic continental shale from northern Qaidam basin was selected as the research object, through the analysis of X-ray diffraction (XRD), field emission scanning electron microscopy (SEM) and nitrogen adsorption experiment, the mineral composition and pore structure characteristics of Jurassic continental shale from the northern Qaidam basin have been investigated in detail. All shale samples studied are quite rich in clay minerals. The clay mineral content ranges from 59.8% to 83.3% with an average of 74.6%, and the brittle mineral content accounts for 16.5% to 39.3%. Nitrogen adsorption test results indicate that for mesopores and macropores of shale samples the average pore width is 2~200 nm, mainly centering on 10~50 nm, and the micropores of the shale samples have a centralized distribution of 0.5~1 nm. The shale samples show high specific surface areas of 4.6~15.2 m2/g. According to SEM results, interparticle mineral matrix pores are main pore type and slit-type pore are well developed.

Nitrogen adsorption on synthetic akaganeite and its structural implications

Clay Minerals ◽  
1977 ◽  
Vol 12 (4) ◽  
pp. 345-352 ◽  
Author(s):  
E. Paterson ◽  
J. M. Tait
Keyword(s):  
Specific Surface ◽  
Electron Micrographs ◽  
Nitrogen Adsorption ◽  
Structural Scheme ◽  
Qualitative And Quantitative ◽  
Surface Areas ◽  
Two Samples ◽  
Specific Surface Areas ◽  
Adsorptive Properties ◽  
Quantitative Assessments

AbstractComparison of the adsorptive properties of two samples of akaganéite prepared by different methods shows that a structural scheme based upon solid rods is much more likely than a previously proposed scheme involving tubes. Specific surface areas, qualitative and quantitative assessments of porosity' and electron micrographs strongly support this structure.

A COMPARISON OF THE X-RAY DIFFRACTION AND NITROGEN ADSORPTION SURFACE AREAS OF CARBON BLACKS AND CHARCOALS

1948 ◽  
Vol 26a (4) ◽  
pp. 236-242 ◽  
Author(s):  
J. C. Arnell ◽  
W. M. Barss
Keyword(s):  
Carbonaceous Material ◽  
Nitrogen Adsorption ◽  
Activation Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Blacks ◽  
Surface Areas ◽  
Crystallite Surface ◽  
Adsorption Surface ◽  
Order Of Magnitude

The surface areas, as determined from X-ray diffraction and low temperature nitrogen adsorption data, were compared for a number of carbon blacks and activated charcoals. Comparative data were also obtained on samples of charcoal at various stages of activation and after calcination. The X-ray diffraction data indicated that all the samples examined were composed of small graphitelike crystallites of the same order of magnitude, which had specific surfaces of about 2500 to 3000 sq. m. per cc. The nitrogen adsorption surface of a highly activated charcoal was found to be about equal to the X-ray surface. It is suggested that the crystallite surface represents the potential adsorption surface of a carbonaceous material and, providing that crystal growth does not occur during activation, the activation process makes these surfaces available to external adsorbate.

scholarly journals Structure, Texture and Catalytic Properties of Pd/SiO2 Catalysts

1996 ◽  
Vol 13 (5) ◽  
pp. 423-431 ◽  
Author(s):  
S.A. El-Hakam ◽  
Awad I. Ahmed ◽  
S.M. Hassan ◽  
H.M. Farage
Keyword(s):  
Active Site ◽  
Metal Content ◽  
Catalytic Properties ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
Surface Areas ◽  
Dehydrogenation Of Cyclohexane ◽  
Adsorption Surface ◽  
Kinetics Of

The structural properties of Pd/silica catalysts have been investigated by means of DTA and X-ray techniques. The X-ray results indicate that Pd metal is the only phase formed. The textural properties were determined using low-temperature nitrogen adsorption. Surface areas were calculated and the dependence of the surface area on the metal content has been discussed. Pore structure analyses indicate the presence of both micro-and meso-pores. The dehydrogenation of cyclohexane was found to be affected by the metal content. The active site for the dehydrogenation process on Pd/silica catalysts consists of one Pd atom. The kinetics of the dehydrogenation exhibit a fractional order.

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