Sintering of Pt/Al2O3 reforming catalysts: EXAFS study of the behavior of metal particles under oxidizing atmosphere

Borgna, Armando; Normand, F. Le; Garetto, Teresita Francisca; Apesteguı́a, C.R.; Moraweck, B.

doi:10.1007/bf00770989

Cited by 68 publications

(50 citation statements)

References 20 publications

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“…On Pt/Al 2 O 3 prepared from chlorinated precursor, Marceau et al [30] indicated the presence of oxy-chlorinated Pt species, which were reduced at 290°C, while Hwang and Yeh [31] reported that dispersed PtO x Cl y species were reduced at a higher reduction temperature (350°C). The high consumption of H 2 (H 2 /Pt = 3.3) in the TPR profile of Pt-Ni/CNTs (I) is in accordance with that already observed on 5% Pt/ZnO [18] or in Pt/Al 2 O 3 [32][33][34][35][36] which was interpreted by the …”

Section: H 2 -Tprsupporting

confidence: 87%

Influence of Preparation Modes on Pt–Ni/CNTs Catalysts Used in the Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

Zhao

et al. 2008

Catal Lett

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Pt-Ni/CNTs catalysts are prepared by different impregnation techniques and different reduction methods (H 2 , HCHO, and KBH 4 ) for the selective hydrogenation of cinnamaldehyde (CMA) to hydrocinnamaldehyde (HCMA) and investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (H 2 -TPR) techniques. The results show that the catalytic selectivity and activity of the Pt-Ni/CNTs catalysts would significantly be improved by using KBH 4 as a reducing agent, due to the electronic synergetic effect of Pt-Ni-B, and 96% for conversion of CMA and 88% for selectivity of HCMA are obtained over Pt-Ni/CNTs catalyst reduced by KBH 4 . Furthermore, the hydrogenation rate of CMA and selectivity of CMA to HCMA over Pt-Ni/CNTs catalyst are significantly improved in the presence of trace base or acid promoters again. The best result (92% for conversion of CMA and 96% for selectivity of HCMA) is obtained when NaOAc is used as base promoter.

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Section: H 2 -Tprsupporting

confidence: 87%

Influence of Preparation Modes on Pt–Ni/CNTs Catalysts Used in the Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

Zhao

et al. 2008

Catal Lett

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“…Three main peaks were observed in all cases. Since hydrogen hexachloroplatinate was used as the platinum precursor, the first two peaks located at 200 and 240°C (II and III) can be referred to as the reduction of threedimensional bulk phase of oxy-or hydroxychlorinated platinum while the high temperature peak located at 360°C (IV) is referred to the reduction of the twodimensional dispersive oxychlorinated platinum [23][24][25].…”

Section: Hydrogen/co Chemisorptionmentioning

confidence: 99%

Enhanced Sulfur Tolerance of Bimetallic PtPd/Al2O3 Catalysts for Hydrogenation of Tetralin by Addition of Fluorine

et al. 2008

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A series of mono-and bi-metallic Pt-Pd/Al 2 O 3 samples with and without F were studied as aromatic hydrogenation catalysts. The effects of changing the order of impregnation of the Pt precursor and F as well as varying the calcination temperature (300-500°C) were investigated. Temperature programmed reduction (TPR) results demonstrate the presence of a higher fraction of dispersed metal precursor species left on the surface from the impregnation (PtO x Cl y ) on the Pt/Al 2 O 3 sample calcined at high temperature. The impregnation of F before the Pt precursor significantly decreases the interaction between the metal and the support. However, this decrease is not observed when F is impregnated after the metal precursor. For the bimetallic Pt-Pd catalysts, the sample prepared adding F before the metal show a higher degree of Pt-Pd interaction than either the parent Pt-Pd/Al 2 O 3 catalyst or the one prepared with F added later. TPD of ammonia result show the increase in strong acid sites when F is present. Activity tests for tetralin hydrogenation in the presence of 350 ppm dibenzothiophene indicate a better sulfur tolerance for all F-promoted catalysts, especially Pt-Pd.

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“…QEXAFS shows that PtO x is formed after calcination. It is most likely that also PtO x particles have the ability to sinter (39) and ultimately form larger Pt particles.…”

Section: The Final Metal-particle Size: Processes Leading To Narrow Pmentioning

confidence: 99%

Understanding the Influence of the Pretreatment Procedure on Platinum Particle Size and Particle-Size Distribution for SiO2 Impregnated with [Pt2+(NH3)4](NO3−)2: A Combination of HRTEM, Mass Spectrometry, and Quick EXAFS

Oudenhuijzen

Kooyman

Tappel

et al. 2002

Journal of Catalysis

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Sintering of Pt/Al2O3 reforming catalysts: EXAFS study of the behavior of metal particles under oxidizing atmosphere

Cited by 68 publications

References 20 publications

Influence of Preparation Modes on Pt–Ni/CNTs Catalysts Used in the Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

Influence of Preparation Modes on Pt–Ni/CNTs Catalysts Used in the Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

Enhanced Sulfur Tolerance of Bimetallic PtPd/Al2O3 Catalysts for Hydrogenation of Tetralin by Addition of Fluorine

Understanding the Influence of the Pretreatment Procedure on Platinum Particle Size and Particle-Size Distribution for SiO2 Impregnated with [Pt2+(NH3)4](NO3−)2: A Combination of HRTEM, Mass Spectrometry, and Quick EXAFS

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