Bimetallic Catalysts .V. Kinetics of the Hydrogenolysis of Butane over Pt-Mo/SiO2 Catalysts

Leclercq, G.; Gharbi, A. El; Pietrzyk, S.

doi:10.1006/jcat.1993.1318

Cited by 12 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hence, the kinetic study of the hydrogenolysis of butane should allow one to discriminate between these two hypotheses. The results of this study have been published in detail in ref , but, for the sake of clarity in our reasoning, we will recall them in some detail.…”

Section: Resultsmentioning

confidence: 99%

Investigation on Active Sites in Pt−Mo on Silica Catalysts for Reactions of Hydrocarbons with Hydrogen

Leclercq¹,

Pietrzyk²,

Romero³

et al. 1997

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

A series of bimetallic catalysts Pt-Mo deposited on silica, with the same (Pt + Mo) metal atom content but various Mo/Mo + Pt ratios, has been synthesized and characterized by XPS, ESR, hydrogen chemisorption, and oxygen uptake during their reoxidation after reduction, in order to determine the oxidation state of Pt and Mo and the catalyst surface compositions. They have been further tested for their activities in the dehydrogenation of cyclohexane, the hydrogenation of benzene, the hydrogenolysis of butane, and the reactions of hexane, on the one hand, and of 3-methylpentane, on the other hand, with hydrogen. Finally the kinetics of butane hydrogenolysis has been extensively studied in order to determine the equilibrium constants of butane adsorption and the rate constants of the steps of C-C bond breaking on all the Pt-Mo/SiO 2 samples. The main results are that, while Pt is completely reduced in a metal state, only a fraction of Mo, which depends only on the reduction temperature, is reduced into metal. Mo at various oxidation states is present in the same proportion for all the bimetallic catalysts. A Mo surface enrichment has been evidenced after reduction in hydrogen, but it has been shown that this enrichment decreases or even disappears in the presence of oxygen and of aromatic hydrocarbons strongly adsorbed on the metal particle surfaces. Two kinds of reactions are distinguished: cyclohexane dehydrogenation, alkanes isomerization, and cyclization, with a ratedetermining step occurring preferably on Pt, and alkanes hydrogenolysis, which is much faster on Pt-Mo because of preferential adsorption on a mixed Pt-Mo site. The nature of Pt and Mo species participating to this mixed site is discussed.

show abstract

Section: Resultsmentioning

confidence: 99%

Investigation on Active Sites in Pt−Mo on Silica Catalysts for Reactions of Hydrocarbons with Hydrogen

Leclercq¹,

Pietrzyk²,

Romero³

et al. 1997

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

show abstract

“…Some techniques for the preparation of molybdenum oxide with a large surface area such as evaporation of the oxide aerosol in a frame reactor , or partial reduction of MoO 3 in the presence of Pt have been reported, but they are not widely used. Therefore, to investigate the interfering effects, Pt and MoO 3 dispersed over alumina, − silica, zeolites, or other supports were usually applied. But, it is necessary to note that the interaction of Pt with a support can be stronger than with molybdenum oxide, which makes the investigation of direct Pt−MoO 3 interactions difficult.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Sulfur Tolerance of Pt−MoO_x Catalysts Prepared from Pt−Mo Alloy Precursors

et al. 2007

View full text Add to dashboard Cite

Novel Pt−MoO x catalytic systems were prepared by the oxidation−reduction of Pt−Mo alloy precursors with different metal contents. According to XRD, SEM, and TEM data, oxidation at 550 °C led to the destruction of initial alloys and the formation of molybdenum oxide and metallic platinum particles. As evidenced by TPR H2, adsorption measurements, and in situ XRD analysis, during reduction in the presence of Pt, molybdenum oxide can trap hydrogen already at ambient temperature with the formation of molybdenum oxide hydroxide or molybdenum bronzes. In contrast to initial alloys, the oxidized systems showed significant catalytic activity in toluene hydrogenation. The results suggested that both metallic platinum and molybdenum oxide contribute to this activity. The sulfur resistance test revealed that Pt−MoO x systems had an enhanced tolerance to sulfur contained in the feed.

show abstract

Preparation, Characterization, and Catalytic Activity of Molybdenum Carbide or Nitride Supported on Platinum Clusters Dispersed in EMT Zeolite

Bécue¹,

Manoli²,

Potvin³

et al. 1999

Journal of Catalysis

View full text Add to dashboard Cite

Bimetallic Catalysts .V. Kinetics of the Hydrogenolysis of Butane over Pt-Mo/SiO2 Catalysts

Cited by 12 publications

References 0 publications

Investigation on Active Sites in Pt−Mo on Silica Catalysts for Reactions of Hydrocarbons with Hydrogen

Investigation on Active Sites in Pt−Mo on Silica Catalysts for Reactions of Hydrocarbons with Hydrogen

Synthesis, Characterization, and Sulfur Tolerance of Pt−MoO_x Catalysts Prepared from Pt−Mo Alloy Precursors

Preparation, Characterization, and Catalytic Activity of Molybdenum Carbide or Nitride Supported on Platinum Clusters Dispersed in EMT Zeolite

Contact Info

Product

Resources

About

Bimetallic Catalysts .V. Kinetics of the Hydrogenolysis of Butane over Pt-Mo/SiO2 Catalysts

Cited by 12 publications

References 0 publications

Investigation on Active Sites in Pt−Mo on Silica Catalysts for Reactions of Hydrocarbons with Hydrogen

Investigation on Active Sites in Pt−Mo on Silica Catalysts for Reactions of Hydrocarbons with Hydrogen

Synthesis, Characterization, and Sulfur Tolerance of Pt−MoOx Catalysts Prepared from Pt−Mo Alloy Precursors

Preparation, Characterization, and Catalytic Activity of Molybdenum Carbide or Nitride Supported on Platinum Clusters Dispersed in EMT Zeolite

Contact Info

Product

Resources

About

Synthesis, Characterization, and Sulfur Tolerance of Pt−MoO_x Catalysts Prepared from Pt−Mo Alloy Precursors