Mutual solid-solid interaction between CuO and sodium oxide-doped alumina

El-Shobaky, G.A.; El-Nabarawy, Th.; Fagal, G.A.; Amin, N. H.

doi:10.1016/0040-6031(89)87054-6

Cited by 21 publications

(30 citation statements)

References 21 publications

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“…The calculated values of E were equal to 56.6 ± 0.6 kJ/mol over the range 0-3.80 wt% Li 2 O, indicating that the addition of Li 2 O to the 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 (1996a) for the case of Li 2 O doping of unloaded Co 3 O 4 solids.…”

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

confidence: 90%

“…In other words, the doping process results in a decrease in the degree of dispersion of the CuO crystallites. Similar results have been reported for Na 2 O doping of the CuO/ Al 2 O 3 system (El-Shobaky et al 1989) …”

Section: X-ray Investigations Of the Pure And Doped Solidssupporting

confidence: 89%

“…Similar increases in the specific surface areas of other catalytic systems due to Li 2 O doping have been reported by the author and coworkers (El-Shobaky et al 1989, 1990, 1997a, 1998a,b, 2000a. The observed increase in the S BET values for solids in the CuO/Al 2 O 3 system due to Li 2 O doping may be attributed to the creation of new pores during the decomposition of the LiNO 3 used as a dopant on heat treatment of the solids at 500ºC (El-Shobaky et al 1998a,b).…”

Section: Specific Surface Areas Of the Pure And Doped Samplessupporting

confidence: 83%

“…1961; Caffrey and Allen 1958;Kuzembaev 1980;Kuzembaev and Tugelbaeva 1980;Mucka 1987Mucka , 1993Arinkar et al 1988;Molt 1986;Youssef et al 1992;El-Shobaky et al 1985, 1988b, 1994a,b, 1996a, 1997b, 1999El-Bohy et al 2000;Al-Noaimi et al 1994) and doping of the catalyst with certain foreign ions (El-Shobaky et al 1988a, 1989, 1996a,b, 1997a, 1998b,c, 2000a.…”

Section: Introductionmentioning

confidence: 99%

“…Irradiation of solid catalysts with -rays effects significant modification in their surface and catalytic properties which are dependent mainly on the nature of the catalysts employed and the catalytic reactions investigated. Thus, -irradiation effected a significant increase in the catalytic activity of (Al-Noaimi et al 1994;El-Shobaky et al 1987, 1988b, 1996a-c, 1997b, 1999. In contrast, the catalytic activities of CuO-ZnO/Al 2 O 3 and Mn 2 O 3 /Al 2 O 3 supported solids decreased in alcohol conversion and H 2 O 2 decomposition when the solid systems were exposed to -irradiation (Youssef et al 1992;El-Shobaky et al 1994a,b;Fagal et al 1998;ElBohy et al 2000).…”

Section: Introductionmentioning

confidence: 99%

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The Effects of Li₂O Doping on the Surface and Catalytic Properties of CuO/Al₂O₃ Solids

El-Shobaky

Radwan

Turky

et al. 2000

Adsorption Science & Technology

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ABSTRACT:The effects of doping CuO/Al 2 O 3 solids with Li 2 O on their 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 of finely powdered solid Al(OH) 3 which had been precalcined at 400ºC; the resulting material was then dried and calcined at 500ºC with copper nitrate dissolved in the least amount of distilled water. The amount of copper oxide in such solids was fixed at 13.5 wt% while the amounts of Li 2 O added varied between 0.19 wt% and 3.80 wt%.The results obtained showed that such Li 2 O doping enhanced the crystallization of the CuO phase to an extent proportional to the amount of dopant added and increased the concentration of surface OH groups. This treatment led to a progressive small increase in the BET surface areas (S BET ) of the treated solids, which attained a maximum limit at 0.76 wt% Li 2 O but decreased upon increasing the dopant concentration above this limit. The addition of 0.76 wt% Li 2 O effected an increase of 14.6% in the S BET values of the treated solids while the addition of 3.80 wt% Li 2 O led to a corresponding decrease of 38.5% in this value.Doping with Li 2 O resulted in a progressive decrease in the catalytic activity of the solids towards CO oxidation by O 2 while the presence of 3.80 wt% Li 2 O effected a decrease of 72.5% in the value of the reaction rate constant measured at 175ºC. In contrast, such treatment of CuO/Al 2 O 3 solids with Li 2 O brought about a progressive increase in their catalytic activity towards H 2 O 2 decomposition, which reached a maximum limit in the presence of 1.90 wt% Li 2 O and then decreased when the amount of Li 2 O added was increased above this limit, falling to values which were smaller than those measured for the pure catalyst samples.The doping process did not modify the activation energy of the catalyzed H 2 O 2 reaction but modified the concentration of the catalytically active constituent present in the system.

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

confidence: 90%

Section: X-ray Investigations Of the Pure And Doped Solidssupporting

confidence: 89%

Section: Specific Surface Areas Of the Pure And Doped Samplessupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Effects of Li₂O Doping on the Surface and Catalytic Properties of CuO/Al₂O₃ Solids

El-Shobaky

Radwan

Turky

et al. 2000

Adsorption Science & Technology

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SOLID‐SOLID INTERACTIONS IN PURE AND Li₂O‐DOPED V₂O₅/AI₂O₃ SYSTEM

Abdalla

El-Shobaky

Hassan

1994

Bulletin des Soc Chimique

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The effects of calcination temperature (500-1000°C) and lithium oxide-doping (4 and 10 mole %) on solid-solid interactions between A1203 and V205 were investigated using DTA, TG and their derivatives together with XRD techniques.The results obtained revealed that no solid-solid interaction between vanadium and aluminium oxides occured at 500°C. These oxides interacted in part, at 650°C to produce AIV04, the completion of this reaction requires a prolonged heating at this temperature. LinO-doping much enhanced the interaction yielding AIV04, the presence of 4 mole %was found sufficient to stimulate the complete conversion of V205 into aluminium vanadate. Aluminium vanadate produced in the case of pure mixed solids decomposed entirely by heating at 750°C giving a well crystallized VnOsand an amorphous alumina. On the other hand, lithium oxide-doping much increased the thermal stability of A N 0 4 at 750°C and led also to the formation of AIV03 and LiV10025 phases.The heating of pure mixed oxides in air at 1000°C resulted in the formation of alpha-alumina (corrundum) together with V2O5. This treatment, in the case of doped mixed solids, effected the formation of alpha-AlnO3, V2O5 and LiVlo025 phases. The last compound was formed at 750°C and remained stable by heating at 1000°C. The promotion effect of Li2O in AIV04 formation was tentatively attributed to dissolution of a small portion of Li2O in V205 lattice with subsequent increase in the mobility of V+5 ions.

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ChemInform Abstract: Mutual Solid‐Solid Interaction Between CuO and Sodium Oxide‐Doped Alumina.

et al. 1989

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Mutual solid-solid interaction between CuO and sodium oxide-doped alumina

Cited by 21 publications

References 21 publications

The Effects of Li₂O Doping on the Surface and Catalytic Properties of CuO/Al₂O₃ Solids

The Effects of Li₂O Doping on the Surface and Catalytic Properties of CuO/Al₂O₃ Solids

SOLID‐SOLID INTERACTIONS IN PURE AND Li₂O‐DOPED V₂O₅/AI₂O₃ SYSTEM

ChemInform Abstract: Mutual Solid‐Solid Interaction Between CuO and Sodium Oxide‐Doped Alumina.

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Mutual solid-solid interaction between CuO and sodium oxide-doped alumina

Cited by 21 publications

References 21 publications

The Effects of Li2O Doping on the Surface and Catalytic Properties of CuO/Al2O3 Solids

The Effects of Li2O Doping on the Surface and Catalytic Properties of CuO/Al2O3 Solids

SOLID‐SOLID INTERACTIONS IN PURE AND Li2O‐DOPED V2O5/AI2O3 SYSTEM

ChemInform Abstract: Mutual Solid‐Solid Interaction Between CuO and Sodium Oxide‐Doped Alumina.

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The Effects of Li₂O Doping on the Surface and Catalytic Properties of CuO/Al₂O₃ Solids

The Effects of Li₂O Doping on the Surface and Catalytic Properties of CuO/Al₂O₃ Solids

SOLID‐SOLID INTERACTIONS IN PURE AND Li₂O‐DOPED V₂O₅/AI₂O₃ SYSTEM