Electronic properties of supported Pd aggregates in relation with their reactivity for 1,3-butadiene hydrogenation

Bertolini, J.C.; Delichère, P.; Khanra, Badal C.; Massardier, J.; Noupa, C.; Tardy, B.

doi:10.1007/bf00774723

Cited by 88 publications

(41 citation statements)

References 8 publications

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“…Using the structural independence established by Boudart and Djéga-Mariadassou [3], they conclude that the active sites are the edges and the corners of the particles. This conclusion is contradictory to the works of De Gouveia et al [4] and Bertolini et al [5] on buta-1,3-diene, Didillon et al [1] on acetylene and Duca et al [6] on ethylene and acetylene showing that small particles (< 2 nm) which have a high fraction of edge and corner atoms exhibit low hydrogenation activities. Particularly, for Pd catalyst obtained by colloidal synthesis, Didillon et al [1] has shown that acid synthesis leads to a number of rotation about 3 times the number of rotation of a catalyst obtained trough basic synthesis for a same particle mean size.…”

Section: Introductioncontrasting

confidence: 57%

“…The key points to explain the differences in activity between the two modes of synthesis seem to be the following. First, the proportion of "invisible" Pd by HRTEM or XRD that is to say the proportion of Pd atomically dispersed which is known to be not active for hydrogenation [4,5]. Second, the degree of aggregation of individual colloidal particles as edges or corner aggregation diminishes the exposition of unsaturated atoms known to be poorly active [13].…”

Section: Xrd Diagramsmentioning

confidence: 99%

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Structural and Morphological Characterization of Alumina Supported Pd Nanoparticles Obtained by Colloidal Synthesis

Ramos-Fernandez

Normand

Sorbier³

2007

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Caractérisation de la morphologie et de la structure de nanoparticules de Pd issues de synthèses colloïdales supportées sur alumine -Des catalyseurs formés par des nanoparticules de palladium supportées sur alumine ont été synthétisés par voie colloïdale. La caractérisation de la structure et de la morphologie des nanoparticules obtenues est effectuée en deux temps. Nous déterminons dans un premier temps les formes possibles à partir de principes physiques. Des images en microscopie électronique en transmission haute résolution et des diffractogrammes de rayons X sont simulés pour les différentes morphologies. Ces simulations nous permettent d'évaluer les limites de ces deux techniques appliquées à ce type d'échantillon. Nous montrons que la microscopie permet de distinguer les différentes morphologies possibles mais qu'elle n'est pas adaptée pour caractériser des lacunes ou des défauts de surface. Nous démontrons que la diffraction des rayons X est une technique très complémentaire également capable d'obtenir des informations sur la structure, la morphologie et la taille même pour d'aussi petits objets. Dans un deuxième temps, les simulations sont comparées aux résultats expérimentaux. Nous montrons ainsi que les deux voies de synthèse, acide et basique, mènent à la même structure et morphologie des nanoparticules. Les nanoparticules de PdO présentent une forme d'octaèdre d'environ 2 nm. Les particules de Pd métalliques sont toujours observées sous forme de cuboctaèdre d'environ 2 nm. La structure identique obtenue pour les deux voies de synthèse ne permet pas d'expliquer les différences d'activité catalytique reportées dans la littérature [Didillon B. et al. (1998)

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Section: Introductioncontrasting

confidence: 57%

Section: Xrd Diagramsmentioning

confidence: 99%

Structural and Morphological Characterization of Alumina Supported Pd Nanoparticles Obtained by Colloidal Synthesis

Ramos-Fernandez

Normand

Sorbier³

2007

Oil & Gas Science and Technology - Rev. IFP

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“…The surface chemical composition (Ca 2 p , O 1 s , P 2 p and Pd 3 d ) is determined in order to understand the chemical environment of Pd species on HAP support (Fig. ) …”

Section: Resultsmentioning

confidence: 99%

“…134 eV) is attributed to the binding energy of PO bonds, whereas the Ca 2 p peak ( c . 346 eV) is deconvoluted into CaO bonds, both of which are linked to the HA structure . The O 1 s peaks ( c .…”

Section: Resultsmentioning

confidence: 99%

Glycerol valorization to lactic acid catalyzed by hydroxyapatite‐supported palladium particles

Shen

Zhang

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUND Catalytic formation of lactic acid from biomass glycerol is a sustainable alternative to the conventional fermentation process starting from carbohydrate and the chemical route using HCN and acetaldehyde. Highly concentrated glycerol can be effectively converted to lactic acid using hydroxyapatite‐supported palladium particles in the presence of NaOH. RESULTS The 3% hydroxyapatite‐supported palladium catalyst (Pd3/HAP) demonstrates excellent activity (TOF = 1274 h−1 for a batch time of 90 min) with a high selectivity (95%) towards lactic acid at 99% glycerol conversion (230 °C, NaOH:glycerol molar ratio = 1.1, and glycerol/total Pd intake = 1926). Under the same reaction conditions, the selectivities of lactic acid were 82% and 90% on Pd0.75/HAP and Pd1.5/HAP catalysts, respectively. The Pd3/HAP catalyst was recycled five times in a batch set‐up without a significant drop in activity and lactic acid selectivity, which is indicative of good catalyst stability. CONCLUSIONS Pd‐based catalysts on available hydroxyapatite supports are efficient catalysts for glycerol selective oxidation. The catalysts possess active PdO and Pd0 species well dispersed on the functionalized hydroxyapatite support. Pd0 nanoparticles and NaOH synergistically catalyze the reaction process. © 2018 Society of Chemical Industry

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“…www.elsevier.com/locate/apcata Applied Catalysis A: General 312 (2006) [1][2][3][4][5][6][7][8][9][10][11] Usually, results in literature report a decrease of the metallic character of the atoms for small particles with an ''electron deficient'' character as initially proposed by Boudart and coworkers [22,23] and then demonstrated in theoretical and experimental studies [24][25][26][27][28][29][30]. As a consequence, the catalytic activity will be perturbed by the changes in adsorption strength and consequently in surface coverage or adsorption mode of reactants and products.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of highly dispersed palladium alumina supported particles: Influence of the particle surface density on physico-chemical properties

Benkhaled

Morin

Pichon

et al. 2006

Applied Catalysis A: General

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Complexation with nitrite ions in aqueous medium was used to prepare highly dispersed Pd8 particles supported on alumina. It has been possible to obtain catalysts with different Pd loading keeping the particle size lower than 1 nm as shown by HRTEM, chemisorption, or extended X-ray absorption fine structure (EXAFS) characterizations, and as a consequence with different particle surface density. We observed that electronic properties measured by IR(CO) or X-ray photoelectron spectroscopy (XPS) measurements are strongly influenced by this last parameter and that the origin of these variations can be related to the different strengths of the interactions of the palladium precursor with the alumina surface sites as shown by low temperature CO adsorption followed by FTIR spectroscopy. On increasing Pd loading, saturation of unsaturated Lewis surface sites follows their acid strength: the more acidic ones are the first to react as germination sites, followed by the medium and finally the weaker sites. These different interactions may explain the variation of electronic properties of such small reduced particles which appears to be very sensitive to the chemical nature of their initial germination site on the oxide support. On the other hand, no such effects were observed on changing the type of alumina (d or g) support, in agreement with the principle of the synthesis method which tends to limit strong interaction with the support. Comparison with Pd8 particles with the same particle size and particle surface density but prepared with the well known grafting of acetylacetonate precursor shows marked differences in terms of electronic properties followed by CO FTIR. This result illustrates the possibility to prepare highly dispersed Pd particles with different physico-chemical properties. #

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Electronic properties of supported Pd aggregates in relation with their reactivity for 1,3-butadiene hydrogenation

Cited by 88 publications

References 8 publications

Structural and Morphological Characterization of Alumina Supported Pd Nanoparticles Obtained by Colloidal Synthesis

Structural and Morphological Characterization of Alumina Supported Pd Nanoparticles Obtained by Colloidal Synthesis

Glycerol valorization to lactic acid catalyzed by hydroxyapatite‐supported palladium particles

Synthesis of highly dispersed palladium alumina supported particles: Influence of the particle surface density on physico-chemical properties

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