Effect of Ag-doping of nanosized FeMgO system on its structural, surface, spectral, and catalytic properties

2012 ◽  
Vol 66 (8) ◽  
Author(s):  
Sahar El-Molla ◽  
Laila Ali ◽  
Nabil Amin ◽  
Anwer Ebrahim ◽  
Hala Mahmoud
Keyword(s):  
Catalytic Activity ◽  
Catalytic Properties ◽  
Textural Properties ◽  
Catalytic Decomposition ◽  
Molar Ratio ◽  
Paramagnetic Species ◽  
Ag Doping ◽  
H2o2 Decomposition ◽  
Physico Chemical ◽  
Structural Surface

AbstractThe effects of Ag-doping on the physico-chemical, spectral, surface, and catalytic properties of the FeMgO system with various Fe2O3 loadings were investigated. The dopant (Ag) molar ratio varied between 0.01 % and 0.05 %. The techniques employed for characterisation of catalysts were TG/DTG, XRD, ESR, N2 adsorption at −196°C, and catalytic decomposition of H2O2 at 25–35°C. The results obtained revealed that the investigated catalysts consisted of nanosized MgO as the major phase, apart from the MgFe2O4 and/or Fe3O4 phases. ESR result of the FeMgO system revealed the presence of paramagnetic species as a result of Ag-doping. The textural properties including SBET, porosity and St were modified by Ag-doping. The doping process with Ag-species improved the catalytic activity of the FeMgO system. Increasing the calcination temperature from 400°C to 800°C increased the catalytic activity (k*30 °C) of 0.05 AgFeMgO in H2O2 decomposition by 21.2 times.

Synthesis and Catalytic Activity of Ni/Ce-MCM-41 Mesoporous Catalysts for Hydrogen Production

2010 ◽  
Vol 1279 ◽  
Author(s):  
J. A. Wang ◽  
J. C. Guevara ◽  
L.F. Chen ◽  
J. Salmones ◽  
M. A. Valenzuela ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Mesoporous Materials ◽  
Textural Properties ◽  
Molar Ratio ◽  
High Catalytic Activity ◽  
Strong Temperature Dependence ◽  
Structural Regularity ◽  
Cerium Ion ◽  
Ion Substitution ◽  
Mcm 41

AbstractCe-containing MCM-41 mesoporous materials with large surface area and ordered pore structure system have been possible to be synthesized through a surfactant-assisted approach. The textural properties and structural regularity of the materials varied with the Si/Ce molar ratio. It is found that the band at 970 cm-1 in the FTIR spectrum of the Ce-MCM-41 mesoporous materials might be used as an indicator of the formation of the Ce-O-Si bond and its intensity as a measure of a degree of cerium ion substitution in the framework of Si-MCM-41. When Ni was loaded on the Ce-MCM-41 support, the Ni/Ce-MCM-41 catalysts show high catalytic activity which has strong temperature dependence. The methane conversion over these catalysts reached 60-75 % with a 100 % selectivity towards hydrogen.

scholarly journals Catalytic activity of nanosized Au/CeO2 catalyst towards H2O2 decomposition and the role of cationic/metallic ratio in its activity

2019 ◽  
Vol 10 (4) ◽  
pp. 317-322
Author(s):  
Ayman Abd El-Moemen
Keyword(s):  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Catalytic Decomposition ◽  
Metallic Gold ◽  
Kinetic Measurements ◽  
H2o2 Decomposition ◽  
Treatment Conditions ◽  
Treated Sample ◽  
Pre Treatment

The catalytic decomposition of H2O2 on differently pre-treated Au/CeO2 catalyst was studied by kinetic measurements at 20-50 °C. The prepared catalyst was subjected to pre-treatment by heating either in oxidative (10% O2/N2) or inert (pure N2)atmosphere at 400 °C. The different oxidation states of gold were determined by X-ray photoelectron spectroscopy measurements. The Au/CeO2 catalyst exhibited an excellent catalytic activity towards H2O2 decomposition. The catalytic activity of oxygen pre-treated sample was about twice higher than that measured for nitrogen pre-treated sample. This finding ran parallel to the amount of Aun+ as determined by XPS, indicating the role played by Aun+ species as the most active catalyst’s constituent. However, one cannot overlook the role of metallic gold in catalyzing the H2O2, decomposition showing small activity compared to that of cationic gold. The average crystallites size of metallic gold particles was found to be 7±0.5 nm independent of the pre-treatment conditions. The apparent activation energy of the catalyzed reaction was found to be 46.5 and 47.8 kJ/mol for oxygen and nitrogen pre-treatment, respectively.

scholarly journals Effect of Ag-doping of nanosized FeAlO system on its structural, surface and catalytic properties

2016 ◽  
Vol 9 ◽  
pp. S1242-S1251 ◽  
Author(s):  
Laila I. Ali ◽  
Sahar A. El-Molla ◽  
Nabil H. Amin ◽  
Anwer A. Ebrahim ◽  
Hala R. Mahmoud
Keyword(s):  
Catalytic Properties ◽  
Ag Doping ◽  
Structural Surface

Catalytic Decomposition of Methane: Effect of Various Factors on Catalytic Properties

2007 ◽  
Vol 544-545 ◽  
pp. 23-26 ◽  
Author(s):  
Hyun Chang Shin ◽  
Hyun Jung Kim ◽  
Dong Shin Yun ◽  
Jung Whan Yoo ◽  
Dong Jin Lee ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Temperature ◽  
Methane Conversion ◽  
Catalytic Properties ◽  
Catalytic Decomposition ◽  
Good Catalytic Activity ◽  
Decomposition Of Methane ◽  
Mesoporous Supports ◽  
Mcm 41

The effect of various reaction factors such as amount of Ni loaded, temperature, and variety of supports on the methane conversion were investigated to obtain higher methane conversion. The high activities were observed over Ni(10 wt%)/SiO2 catalyst and at 650oC of reaction temperature. Catalysts using mesoporous supports such as SiO2 and MCM-41 showed good catalytic activity and stability.

Effect of Ag-doping of Nanosized FeAlO System on its Structural, Surface and Catalytic Properties

2011 ◽  
Vol 02 (02) ◽  
Author(s):  
Laila I. Ali ◽  
Sahar A. El-Molla ◽  
Nabil H. Amin ◽  
Anwer A. Ebrahim
Keyword(s):  
Catalytic Properties ◽  
Ag Doping ◽  
Structural Surface

scholarly journals Waste to Catalyst: Synthesis of Catalysts from Sewage Sludge of the Mining, Steel, and Petroleum Industries

2020 ◽  
Vol 12 (23) ◽  
pp. 9849
Author(s):  
Gabriela Castro-León ◽  
Erik Baquero-Quinteros ◽  
Bryan G. Loor ◽  
Jhoselin Alvear ◽  
Diego E. Montesdeoca Espín ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Sewage Sludge ◽  
Catalytic Properties ◽  
Catalytic Decomposition ◽  
Organic Content ◽  
Effluent Treatment ◽  
Manufacturing Companies ◽  
Waste Sludge ◽  
Catalytic Material ◽  
Recovery Technique

The generation of sewage sludge presents a problem for several manufacturing companies as it results from industrial processes or effluent treatment systems. The treatment of this type of waste requires high economic investment, for this reason, it is necessary to find alternatives to recover the valuable materials of the sludges. In this study, metal catalysts were synthesized using waste sludge from the steel, mining, and hydrocarbon industries. The waste sludge was subjected to thermal treatments for the removal of organic content and the reduction of metals with hydrogen current to activate their catalytic properties. The sludge and synthesized catalysts were analyzed to determine their physical, chemical, thermoenergetic, and catalytic properties. Catalytic activity was evaluated using CO chemisorption and by thermal–catalytic decomposition of crude oil. The best conditions for synthesizing the catalysts were a calcination temperature between 300 and 500 °C and a reduction temperature between 300 and 900 °C. The catalysts presented a specific surface between 2.33 and 16.78 m2/g. The catalytic material had a heat capacity between 0.7 and 1.2 kJ/kg∙K. The synthesized materials presented catalytic activity comparable to that of commercial catalysts. With this recovery technique, the industrial waste can be valorized, obtaining catalyst derived from the sludges and promoting the circular economy of manufacturing companies.

Complexation with Hydroxypropyl-gama-Cyclodextrin of Birch Tree Extract Physico-chemical Characterisation of their Binary Products

2008 ◽  
Vol 59 (6) ◽  
Author(s):  
Codruta Soica ◽  
Cristina A. Dehelean ◽  
Valentin Ordodi ◽  
Diana Antal ◽  
Vicentiu Vlaia
Keyword(s):  
Inclusion Complexes ◽  
Water Solubility ◽  
In Vitro Dissolution ◽  
Molar Ratio ◽  
Bark Extract ◽  
Birch Bark ◽  
Preparation Methods ◽  
Birch Tree ◽  
Physico Chemical

Birch bark contains important pentacyclic triterpens that determine an anticancer, anti-inflammatory and antiviral activity. The compounds can be extracted by simple procedures with organic solvents. The major problem of this type of triterpens is their low water solubility which can be increased by physical procedures like cyclodextrin complexation. The aim of present study was to analyse the products between birch bark extract and hydroxypropyl-g -cyclodextrin. Hydroxypropyl-g -cyclodextrin (HPGCD) was used as a host to improve its solubility in water, via inclusion complex formation. In order to obtain the inclusion complexes, 1:2 molar ratio and two preparation methods (physical mixing, kneading) were used. The inclusion complexes were analyzed by in vitro dissolution tests, thermal analysis and X-ray diffraction.

Decomposition of hydrogen peroxide on a two-component NiO-CdO catalyst and the effect of ionizing radiation on its catalytic properties

1979 ◽  
Vol 44 (4) ◽  
pp. 1015-1022 ◽  
Author(s):  
Viliam Múčka
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Nickel Oxide ◽  
Catalytic Properties ◽  
Cadmium Oxide ◽  
Chemisorb Oxygen ◽  
Composition Region ◽  
Chemisorbed Oxygen ◽  
Two Component

The catalytic properties of two-component catalyst nickel oxide-cadmium oxide with the proportions of the components covering the whole composition region 0-100% were examined by studying the decomposition of hydrogen peroxide in aqueous solution on it. In the range 0-25 mol.% CdO, cadmium oxide is found to affect infavourably the ability of nickel oxide to chemisorb oxygen. The amount of the chemisorbed oxygen increases several times on gamma irradiation of the samples. The effect of cadmium oxide on the catalytic activity of the system shows up in fresh samples only indirectly via the changed amount of the oxygen chemisorbed. In older samples the initial catalytic activity of the system is changed, which can be explained based on the concept of bivalent catalytic centres in terms of the co-action of the catalytic centres of the two oxides, which are in equilibrium. The irradiation of the system under study speeds up the processes leading to the establishing of this equilibrium which is thermally very stable, and results in a substantial increase of the catalytic activity of the samples investigated.

Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Extreme Values ◽  
Catalytic Properties ◽  
Active Components ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Peroxide Decomposition ◽  
Two Component ◽  
Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

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