Physicochemical and Catalytic Properties of Spinels Formed by Solid-Solid Interaction Between Fe2O3and V2O5

1996 ◽  
Vol 61 (8) ◽  
pp. 1131-1140 ◽  
Author(s):  
Abd El-Aziz Ahmed Said
Keyword(s):  
Vanadium Oxide ◽  
Active Sites ◽  
Catalyst Surface ◽  
Catalytic Properties ◽  
Flow System ◽  
Oxide Catalysts ◽  
X Ray Diffraction ◽  
Selective Catalyst ◽  
X Ray ◽  
Solid Catalysts

Vanadium oxide catalysts doped or mixed with 1-50 mole % Fe3+ ions were prepared. The structure of the original samples and those calcined from 200 up to 500 °C were characterized by TG, DTA, IR and X-ray diffraction. The SBET values and texture of the solid catalysts were investigated. The catalytic dehydration-dehydrogenation of isopropanol was carried out at 200 °C using a flow system. The results obtained showed an observable decrease in the activity of V2O5 on the addition of Fe3+ ions. Moreover, Fe2V4O13 is the more active and selective catalyst than FeVO4 spinels. The results were correlated with the active sites created on the catalyst surface.

Surface Studies and Nature of Active Sites of Supported Heteropolyacids as Catalysts in Methanol Dehydration

1994 ◽  
Vol 59 (4) ◽  
pp. 820-832 ◽  
Author(s):  
Amin Anwar ◽  
Ali Abdel-Ghaffar ◽  
Sameh Aboul-Fotouh ◽  
Ebeid Fikry
Keyword(s):  
Atmospheric Pressure ◽  
Active Sites ◽  
Pore Radius ◽  
Catalytic Properties ◽  
Flow System ◽  
Total Pore Volume ◽  
X Ray Diffraction ◽  
Active Centers ◽  
X Ray ◽  
The Mean

Different amounts of molybdo- and tungstophosphoric acids were supported on α-Al2O3 to get information about their surface and catalytic properties. The surface study revealed that surface area, total pore volume and the mean pore radius decreased as the acid content increased. X-Ray diffraction analysis showed that there is no interaction between the acid and α-Al2O3. Using a continuous flow system, methanol transformation was carried out under atmospheric pressure. Some experiments were made to determine the nature of active centers and reaction mechanism.

Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said
Keyword(s):  
Active Sites ◽  
Isopropyl Alcohol ◽  
Oxide Catalyst ◽  
Flow System ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalyst Composition ◽  
Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

scholarly journals Enhancement of Mercury Removal by Utilizing Catalytic Chelation Technique

2020 ◽  
Vol 10 (5) ◽  
pp. 6354-6364
Keyword(s):  
Heavy Metals ◽  
Active Sites ◽  
Catalyst Surface ◽  
Chelating Agent ◽  
Xrd Analysis ◽  
Mercury Removal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cold Vapor Atomic Absorption ◽  
Time Of Reaction

Discharge of heavy metals released from industries has adverse effects on the environment. The development of a method that can safely remove heavy metals is still challenging. Therefore, the aim of this study is to propose catalytic chelation technique for the removal of mercury (Hg). Removal of Hg was carried out using the sodium acetate (CH3COONa) as the chelating agent and catalyzed by the heterogeneous alumina supported calcium oxide (CaO/Al2O3). The optimization was performed by applying the Response Surface Methodology (RSM) with the pH ranging from 7 to 10, a dosage of chelating agent from 400 ppm to 600 ppm, temperature from 33.5 to 37.5 oC, and time of reaction from 1 to 5 h. Hg content analysis was carried out using Flow Injection Mercury System based on cold vapor atomic absorption spectroscopy. X-ray diffraction (XRD) analysis revealed the presence of active sites on the catalyst. Field Emission Scanning Electron Microscopy (FESEM) analysis represented the formation of homogeneous particles on the catalyst surface. The Brunauer-Emmett-Teller (BET), Energy Dispersive X-Ray (EDX), and Fourier-transform Infrared Spectroscopy (FTIR) confirmed the surface area, the elemental composition, and functional groups of the catalyst, respectively. Moreover, the proposed method successfully achieved ±99 % of Hg removal.

Facile Solid State Method Route Synthesis and Enhance Visible Light Activities of BiVO4 by Doping Co

2016 ◽  
Vol 703 ◽  
pp. 316-320
Author(s):  
Hai Feng Chen ◽  
Jing Ling Hu ◽  
Bing Xu
Keyword(s):  
Solid State ◽  
Visible Light ◽  
Catalytic Effect ◽  
Catalytic Properties ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Illumination Time ◽  
X Ray ◽  
State Method

Using NH4VO3, Bi (NO3)3•5H2O and Co (NO3)2•6H2O as raw materials, Co doped BiVO4 (Co/BiVO4) photocatalysts were successfully prepared by solid state method. And the photo catalytic properties were test in this work. Crystal structures of these samples were characterized by X-ray diffraction (XRD). The Methyl Orange (MO) was simulated as the sewage under the visible light to explorer the influence of the illumination time and the mass of photocatalyst. The visible-light absorption spectrum of BiVO4 was broadening with doping Co. It was found that the Co/BiVO4 had higher photocatalytic activity than pure BiVO4 .The reason of enhanced catalytic effect also had been analyzed and discussed in the article.

Preparation and Application of Lead Dioxide Electrode for Zinc Electrolysis

2013 ◽  
Vol 785-786 ◽  
pp. 1125-1129
Author(s):  
Xiao Yong Yang ◽  
Pei Xian Zhu ◽  
Yun Sen Si
Keyword(s):  
Surface Characterization ◽  
Catalytic Properties ◽  
Lead Dioxide ◽  
Manufacturing Cost ◽  
X Ray Diffraction ◽  
Simulation Test ◽  
X Ray ◽  
Zinc Smelter ◽  
Lead Dioxide Electrode

According to the process of anodic oxygen evolution in sulfate system for zinc electrolysis,Ti-base lead dioxide electrode can be prepared to use in this case.The surface characterization of the electrode was studied by Scanning electron microscopy(SEM) and X-ray diffraction(XRD).The electrode lifetime was tested in 1mol/L H2SO4solution at 60°C,and the electro-catalytic properties was examined by polarization curves.Then these samples was enlarged and simulation test was conducted at Mengzi marriage zinc smelter in Yunnan.The results show that the electro-catalytic properties is better and the electrodes lifetime is longer compared to the traditional lead electrode.Moreover,it has a significant effect in reducing energy consumption, manufacturing cost and improving the production and grade of zinc.

scholarly journals Synthesis, Crystal Structure and Magnetic Properties of Bixbyite-type Vanadium Oxide Nitrides

2009 ◽  
Vol 64 (3) ◽  
pp. 281-286 ◽  
Author(s):  
Suliman Nakhal ◽  
Wilfried Hermes ◽  
Thorsten Ressler ◽  
Rainer Pöttgen ◽  
Martin Lerch
Keyword(s):  
Crystal Structure ◽  
Vanadium Oxide ◽  
Magnetic Ordering ◽  
Vanadium Oxides ◽  
Detectable Amount ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vanadium Sulfide ◽  
Structure Result ◽  
X Ray Absorption

Ammonolysis of vanadium sulfide leads to the formation of bixbyite-type vanadium oxide nitrides. Small amounts of nitrogen incorporated in the structure result in the stabilization of the bixbyite type not known for vanadium oxides. The crystal structure was investigated using X-ray diffraction and X-ray absorption spectroscopy. At temperatures above 550 °C the powders decompose to corundumtype V2O3 containing no detectable amount of nitrogen. Below 39 K magnetic ordering is observed.

scholarly journals Solvothermally derived Me2(H2O)4(5SSA)3·DMF and Me2(H2O)4(4NSA)2·DMF: Application as Biginelli reaction catalysts

Chemija ◽  
2019 ◽  
Vol 30 (2) ◽  
Author(s):  
Andrius Laurikėnas ◽  
Fatma Yalçin ◽  
Robertas Žilinskas ◽  
Ayse Uztetik Morkan ◽  
Albinas Žilinskas ◽  
...  
Keyword(s):  
Solvothermal Synthesis ◽  
Catalytic Properties ◽  
Inorganic Compounds ◽  
Biginelli Reaction ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Compounds ◽  
Phase And Chemical Composition ◽  
Scanning Electron

The solvothermal synthesis between Me(NO3)x ∙ yH2O (Mex+ = Fe3+, Ni2+, Mn2+, Co2+, Cu2+) and respectively 4-nitrosalycilic (4NSA) and 5-sulfosalicylic (5SSA) acids produced hybrid organic-inorganic compounds composed of Mex+ ions and organic fragments which include three different functional groups, carboxylic, hydroxyl and sulfonic, each coordinated to the Mex+ ions. The phase and chemical composition, microstructure and properties of Me2(H2O)4(5SSA)3·DMF and Me2(H2O)4(4NSA)2·DMF (DMF – dimethylformamide) hybrid compounds were evaluated and discussed. The synthesised materials were characterised by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy. The catalytic properties of the obtained compounds were also investigated.

scholarly journals In-Exchanged CHA Zeolites for Selective Dehydrogenation of Ethane: Characterization and Effect of Zeolite Framework Type

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 807
Author(s):  
Zen Maeno ◽  
Xiaopeng Wu ◽  
Shunsaku Yasumura ◽  
Takashi Toyao ◽  
Yasuharu Kanda ◽  
...  
Keyword(s):  
Active Sites ◽  
Temperature Programmed Desorption ◽  
X Ray Diffraction ◽  
Zeolite Framework ◽  
X Ray ◽  
Catalytic Activities ◽  
Ethane Dehydrogenation ◽  
Temperature Programmed

In this study, the characterization of In-exchanged CHA zeolite (In-CHA (SiO2/Al2O3 = 22.3)) was conducted by in-situ X-ray diffraction (XRD) and ammonia temperature-programmed desorption (NH3-TPD). We also prepared other In-exchanged zeolites with different zeolite structures (In-MFI (SiO2/Al2O3 = 22.3), In-MOR (SiO2/Al2O3 = 20), and In-BEA (SiO2/Al2O3 = 25)) and different SiO2/Al2O3 ratios (In-CHA(Al-rich) (SiO2/Al2O3 = 13.7)). Their catalytic activities in nonoxidative ethane dehydrogenation were compared. Among the tested catalysts, In-CHA(Al-rich) provided the highest conversion. From kinetic experiments and in-situ Fourier transform infrared (FTIR) spectroscopy, [InH2]+ ions are formed regardless of SiO2/Al2O3 ratio, serving as the active sites.

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