The sintering of supported metal catalystsI. Redispersion of supported platinum in oxygen

Fiedorow, R.; Wanke, Sieghard E.

doi:10.1016/0021-9517(76)90290-6

Cited by 140 publications

(46 citation statements)

References 13 publications

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“…The particle size remarkably increased with increasing O 2 content. It is known that Pt-supported on alumina sinters easily under oxidative conditions [12][13][14]. The results shown in Fig.…”

Section: Sintering Behaviormentioning

confidence: 82%

“…Sintering of noble metals has been widely investigated and the sintering rate of noble metals is largely dependent on the experimental conditions, e.g., substrate morphology, purities of catalyst species and support materials, composition of ageing atmospheres, temperature, and time [12][13][14][15][16][17]. In particular, ageing atmosphere in high temperature region was the key point for noble metal sintering through our experience.…”

Section: Sintering Behaviormentioning

confidence: 99%

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Noble Metal Sintering Suppression Technology in Three-way Catalyst: Automotive Three-way Catalysts with the Noble Metal Sintering Suppression Technology Based on the Support Anchoring Effect

Shinjoh

2009

Catal Surv Asia

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Section: Sintering Behaviormentioning

confidence: 82%

Section: Sintering Behaviormentioning

confidence: 99%

Noble Metal Sintering Suppression Technology in Three-way Catalyst: Automotive Three-way Catalysts with the Noble Metal Sintering Suppression Technology Based on the Support Anchoring Effect

Shinjoh

2009

Catal Surv Asia

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“…Particle fragmentation and recrystallization has been observed for a number of high-temperature oxidation systems [25]. This effects was used by Friedorow and Wanke [26], Ruckenstein and Malhotra [27] and Flynn and Wanke [28] to redisperse Al 2 O 3 supported Pt particles which had sintered after hightemperature treatment in hydrogen. These results are also in agreement with recent findings of Yang et al who found that oxygen treatment at about 670 K leads to a disrupture of supported Ag particles to smaller subunits [29].…”

Section: K Tmentioning

confidence: 99%

High temperature partial oxidation reactions over silver catalysts

Nagy

Mestl

1999

Applied Catalysis A: General

176

115

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In honor of Prof. Dr. Wolfgang Sachtler´s 75 th birthday. AbstractThe exceptional catalytic activity of silver for a number of partial oxidation reactions has been known for nearly a century. Despite the wid espread use of silver in heterogeneous catalysis, there still remain unresolved questions about the mechanistic details of reaction. The ethylene epoxidation and formaldehyde synthesis reactions are the two industrially-relevant reactions which have received, by far, the most attention. The importance of these reactions cannot be underestimated. Both ethylene epoxide and formaldehyde serve as primary chemicals for a wide variety of materials which find use in an enormous number of products. There is, therefore, a great scientific and economi c motivation for understanding these reactions and for unraveling the secret to the exceptional catalytic a ctivity of silver. This contribution in honor of Prof. W. Sachtler´s 75 th birthday summarizes recent results obtained in our laboratory on the formaldehyde synthesis reaction and the oxidative coupling of methane as a laboratory test reaction. The article shows that the formation of bulk-dissolved oxygen species is critical to activation of the silver for reaction. Both the chemical composition and the bulk morphology of the catalyst are strong functions of the gas-phase composition and reaction temperature. Similar apparant activation energies determined for oxygen diffusion and oxidative coupling of methane suggest that the rate limiting step of the oxidative coupling of methane over silver is the diffusion of bulk-dissolved oxygen to silver (111) surfaces at which oxygen rapidly reacts with methane.

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“…Johnson and Keith (1963) had investigated this phenomena and observed that in the presence of oxygen partial pressure there is a tendency for the oxide to form, and the oxidized state would be stabilized by the complex. This decrease in Pt-Al2O3-CI2 complex formation beyond a temperature of 550°C was thought to be primarily related to the decrease in metal surface area, support surface area to a certain extent and chlorine loss Figures 5, 6, and 7 (Fiedorow and Wanke, 1976). From these suggestions it can be concluded that Pt-Al2O3-CI2 complex formation after treatment in an oxidizing atmosphere is responsible for enhanced catalyst cracking activity resulting in higher benzene yield.…”

Section: Effect Of Oxygen Atmospherementioning

confidence: 94%

Cracking properties of some reforming catalysts

Al-Madfai¹,

Abbas

Ali

1986

Can J Chem Eng

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The cracking properties of industrial reforming catalysts of y-alumina loaded with 0.6% Pt, with 0.35% Pt, and with 0.35% Pt plus promoters were investigated. The mode of cracking of these catalysts was studied after treatment under different oxidation and reducing atmospheres. Cumene cracking was used as a model reaction. The cracking products were collected and analysed, and the quantity of benzene produced was used to compare the activities of these catalysts. Maximum cracking was observed around 550°C for all catalysts studied. Cracking rates differed for various treatment conditions for the same catalyst, normally increasing after oxidation treatment. Marked changes in the cracking activity of unloaded y-alumina were observed after it was chlorinated. Benzene yield was studied in relation to possible complex formation of Pt-AI2O3-Cl2.On a CtudiC les propriCtCs de craquage de catalyseurs de reformage industriels constituCs d'alumine-y chargCe avec 0,6% de Pt, 0,35% de Pt ou 0,35% de Pt et de promoteurs. Le mode de craquage de ces catalyseurs a CtC Ctudit aprbs

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The sintering of supported metal catalystsI. Redispersion of supported platinum in oxygen

Cited by 140 publications

References 13 publications

Noble Metal Sintering Suppression Technology in Three-way Catalyst: Automotive Three-way Catalysts with the Noble Metal Sintering Suppression Technology Based on the Support Anchoring Effect

Noble Metal Sintering Suppression Technology in Three-way Catalyst: Automotive Three-way Catalysts with the Noble Metal Sintering Suppression Technology Based on the Support Anchoring Effect

High temperature partial oxidation reactions over silver catalysts

Cracking properties of some reforming catalysts

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