Surface and catalytic properties of γ-irradiated Fe2O3Cr2O3/Al2O3 solids

El-Shobaky, G.A.; Fagal, G.A.; El-Shobaky, H.G.; El-Khouly, Sahar M.

doi:10.1016/s0927-7757(98)00855-3

Cited by 19 publications

(38 citation statements)

References 26 publications

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“…Similar results have been reported for Na 2 O and Li 2 O doping of the CuO/Al 2 O 3 system , 2000b and of the CuO-ZnO/Al 2 O 3 system (El-Shobaky et al 1998a,b).…”

Section: Resultssupporting

confidence: 84%

“…Similar results have been obtained for ZnO doping of the CuO/Al 2 O 3 system (El-Shobaky et al 2001a) and the Co 3 O 4 /Al 2 O 3 system (Chin and Hercules 1982;El-Shobaky et al 2001b). Such findings indicate that ZrO 2 doping led to an increase in the degree of dispersion of the CuO phase in the CuO/Al 2 O 3 system.…”

Section: Resultssupporting

confidence: 80%

“…The calculated values of DE thus obtained were equal to 83 ± 3 kJ/mol over the range 0-10 wt% CeO 2 or ZrO 2 added, thereby indicating that the addition of small amounts of such dopants to CuO/Al 2 O 3 solids did not change the activation energy of the catalyzed reaction but rather modified the concentration of catalytically active constituents in the system. Similar results have been reported by El-Shobaky et al (2000b) when the CuO/Al 2 O 3 system was subjected to doping by Li 2 O.…”

Section: Catalytic Decomposition Of H 2 O 2 Over the Pure And Varioussupporting

confidence: 89%

“…Such findings indicate that ZrO 2 doping led to an increase in the degree of dispersion of the CuO phase in the CuO/Al 2 O 3 system. This could be tentatively attributed to a possible coating of the CuO crystallites with a ZrO 2 film which hindered the particle adhesion process, thereby limiting grain growth during the course of heat treatment (El-Shobaky et al 2000b). …”

Section: Resultsmentioning

confidence: 99%

“…The catalytic activity and stability of CuO can be greatly improved by loading it on to finely divided support materials, doping the solid with certain foreign oxides and treating the same with ionizing radiation. CeO 2 and g-Al 2 O 3 have been used as convenient supports for precious metals and copper oxide catalysts (Yao and Yao 1984;Lin and Stephanopoulos 1995a,b;Luo et al 1997;El-Shobaky et al 1988, 1990. Use of a support material increases the degree of dispersion of catalytically active constituents and hinders their grain growth, thereby increasing their catalytic activities and stabilities.…”

Section: Introductionmentioning

confidence: 99%

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Surface and Catalytic Properties of the CuO/Al₂O₃ System as Influenced by Doping with CeO₂ or ZrO₂ and by γ-Irradiation

El-Shobaky

Radwan

Turky

et al. 2001

Adsorption Science & Technology

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ABSTRACT:The effects of doping the CuO/Al 2 O 3 system with CeO 2 or ZrO 2 , or alternatively treatment with g-irradiation, on its surface and catalytic properties were investigated using nitrogen adsorption at -196ºC, the decomposition of H 2 O 2 at 20-40ºC and the oxidation of CO by O 2 at 175ºC. The pure solids were prepared by wet impregnation with copper nitrate dissolved in the least amount of distilled water of finely powdered solid Al(OH) 3 precalcined at 400ºC, followed by drying the resulting product and subjecting the same to calcination at 500ºC. The doped solids were prepared by treating Al(OH) 3 precalcined at 400ºC with a known amount of dopant, i.e. cerium or zirconyl nitrate dissolved in the least amount of distilled water, prior to impregnation with the copper nitrate solution. The amount of copper oxide thus introduced was fixed at 13.5 wt% while the amounts of dopants were varied between 1 wt% and 10 wt% CeO 2 or ZrO 2 .The results obtained indicated that ZrO 2 doping increased the degree of dispersion of the CuO phase, while CeO 2 treatment had the reverse effect. Doping the CuO/Al 2 O 3 system with CeO 2 or ZrO 2 led to an increase of 15.4% or 8.1%, respectively, in its BET surface area. The catalytic activity of the system towards the decomposition of H 2 O 2 decreased on doping with ZrO 2 but increased when CeO 2 was used as a dopant. g-Irradiation (at 20-160 Mrad) of CuO/Al 2 O 3 solids resulted in a measurable and progressive decrease in their catalytic activity towards H 2 O 2 decomposition.In CO oxidation with O 2 , ZrO 2 treatment of the CuO/Al 2 O 3 solids brought about a progressive increase in their catalytic activity with the maximum value (a 31% increase) being observed in the presence of 3 wt% ZrO 2 but then decreasing with further increases in the amount of dopant present until the final value attained with 10 wt% ZrO 2 was smaller than that measured for the pure CuO/Al 2 O 3 catalyst sample. In contrast, the addition of the smallest amount of CeO 2 (1 wt%) led to an effective increase of 69% in the catalytic activity of the CuO/Al 2 O 3 system towards the O 2 oxidation of CO, which then decreased when further amounts of CeO 2 were added to the system although still exhibiting a catalytic activity greater than that of the undoped catalyst sample.Doping or g-irradiation of the CuO/Al 2 O 3 system had no influence on the activation energy for the decomposition of H 2 O 2 in the presence of the resulting solid catalysts although the concentrations of catalytically active sites present on the surfaces of the solids investigated were modified by such treatment.

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“…Similar results have been reported for Na 2 O and Li 2 O doping of the CuO/Al 2 O 3 system , 2000b and of the CuO-ZnO/Al 2 O 3 system (El-Shobaky et al 1998a,b).…”

Section: Resultssupporting

confidence: 84%

Section: Resultssupporting

confidence: 80%

Section: Catalytic Decomposition Of H 2 O 2 Over the Pure And Varioussupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Surface and Catalytic Properties of the CuO/Al₂O₃ System as Influenced by Doping with CeO₂ or ZrO₂ and by γ-Irradiation

El-Shobaky

Radwan

Turky

et al. 2001

Adsorption Science & Technology

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Removal of methyl orange from aqueous solutions by magnetic maghemite/chitosan nanocomposite films: Adsorption kinetics and equilibrium

Jiang

Zhu

et al. 2012

J of Applied Polymer Sci

141

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Magnetic maghemite (γ‐Fe2O3)/chitosan nanocomposite films were prepared by solution casting method and characterized by Fourier transform infrared spectra, thermogravimetric analysis, differential scanning calorimetry and X‐ray diffraction. Batch adsorption experiments were carried out utilizing the composite films to adsorb a typical azo dye, i.e., methyl orange (MO) from aqueous solutions. The effects of adsorbent dosage, solution pH, coexisting anions, and temperature were studied. Adsorption kinetic was verified by pseudo‐first‐order and pseudo‐second‐order kinetic models. Results indicated that the rate of dye adsorption followed pseudo‐second‐order kinetic model for the initial dye concentration range studied. MO adsorption onto magnetic γ‐Fe2O3/chitosan composite films was better described by Langmuir isotherm. Thermodynamic studies showed that MO adsorption was exothermic and spontaneous in nature. Because magnetic maghemite/chitosan nanocomposite films could be recovered conveniently and possessed of excellent adsorptive property, it can be developed as an economical and alternative adsorbent to decolorize or treat dye wastewater. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

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Nickel cuprate supported on cordierite as an active catalyst for CO oxidation by O2

El-Shobaky

Fahmy

2006

Applied Catalysis B: Environmental

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Surface and catalytic properties of γ-irradiated Fe2O3Cr2O3/Al2O3 solids

Cited by 19 publications

References 26 publications

Surface and Catalytic Properties of the CuO/Al₂O₃ System as Influenced by Doping with CeO₂ or ZrO₂ and by γ-Irradiation

Surface and Catalytic Properties of the CuO/Al₂O₃ System as Influenced by Doping with CeO₂ or ZrO₂ and by γ-Irradiation

Removal of methyl orange from aqueous solutions by magnetic maghemite/chitosan nanocomposite films: Adsorption kinetics and equilibrium

Nickel cuprate supported on cordierite as an active catalyst for CO oxidation by O2

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Surface and catalytic properties of γ-irradiated Fe2O3Cr2O3/Al2O3 solids

Cited by 19 publications

References 26 publications

Surface and Catalytic Properties of the CuO/Al2O3 System as Influenced by Doping with CeO2 or ZrO2 and by γ-Irradiation

Surface and Catalytic Properties of the CuO/Al2O3 System as Influenced by Doping with CeO2 or ZrO2 and by γ-Irradiation

Removal of methyl orange from aqueous solutions by magnetic maghemite/chitosan nanocomposite films: Adsorption kinetics and equilibrium

Nickel cuprate supported on cordierite as an active catalyst for CO oxidation by O2

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Surface and Catalytic Properties of the CuO/Al₂O₃ System as Influenced by Doping with CeO₂ or ZrO₂ and by γ-Irradiation

Surface and Catalytic Properties of the CuO/Al₂O₃ System as Influenced by Doping with CeO₂ or ZrO₂ and by γ-Irradiation