Electronic effects in the coke deactivation of platinum-alumina catalysts

Векки, А. В. де; Kraev, Yu. L.; Solovykh, A. I.

doi:10.1134/s0965544108030079

Cited by 2 publications

(2 citation statements)

References 2 publications

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“…Our previous study found that this coke had a low oxidation temperature in the TGA profile because of the catalytic effect of Pt metal in oxidation reactions [15]. By using quantumchemical calculations, Vekki et al [29] show that the electron density of Pt supported on Al 2 O 3 increases significantly when aromatic and poly-aromatic rings chemically adsorb on Pt sites, and, in the case of graphitic carbon, the Pt sites gain the richest electron density, comparable to other compounds.…”

Section: Resultsmentioning

confidence: 93%

Electronic density enrichment of Pt catalysts by coke in the propane dehydrogenation

Song

Park

et al. 2010

Korean J. Chem. Eng.

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We investigated the nature of coke generated in propane dehydrogenation over supported Pt catalysts by FTIR, NMR, and XPS. NMR and FTIR spectra proved that the coke produced in the reaction contained poly-aromatic rings, which was consistent with the previous result that pregraphite-like coke structure was formed. The XPS results indicated that the coke deposits consisted of sp 2 hybridized carbon. All of the characterizations indicated that the pregraphite-like coke containing the poly-aromatic ring structure was generated over the catalysts during the propane dehydrogenation. Furthermore, the XPS measurement demonstrated that the coke deposits interacted with Pt and the electron density of Pt was enriched through the interaction.

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Section: Resultsmentioning

confidence: 93%

Electronic density enrichment of Pt catalysts by coke in the propane dehydrogenation

Song

Park

et al. 2010

Korean J. Chem. Eng.

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“…Transition metal nanoparticles supported on metal oxide supports have been used as heterogeneous catalysts for a variety of catalytic applications including oxidation reactions and activation of hydrocarbons. − Two of the major mechanisms that deactivate a nanoparticle catalyst are sintering of the nanoparticles and coking. Sintering of the small clusters results in larger particles that reduce the surface area of the metal and negates the unique properties of the nanoparticles. − Coking reduces the activity of the catalyst by coating the metal particle with carbon or other intermediates that block the active sites. − Thus one of the major challenges in developing nanoparticle catalysts is identifying and understanding strategies for minimizing coking and sintering while maintaining the activity.…”

Section: Introductionmentioning

confidence: 99%

Effect of Embedding Platinum Clusters in Alumina on Sintering, Coking, and Activity

Reber

2017

J. Phys. Chem. C

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First-principles theoretical studies of Pt n (n = 1–7) clusters supported on pristine α-Al2O3 (0001) and embedded in vacancies in the alumina surface have been carried out to investigate the effect of embedding and overcoating on coking, sintering, and catalytic activity. The hydrogen adsorption energy and the ethylene adsorption energy are used as proxies for estimating the cluster’s relative activity for C–H bond activation and coking. The embedded clusters are found to exhibit enhanced stability, indicating that they are less prone to sintering. The hydrogen and ethylene adsorption energy of platinum clusters supported on pristine α-Al2O3 are found to be correlated, suggesting that an increase in activity will also cause an increase in coking. Embedded clusters offer a pathway to maintain the catalytic activity while reducing the coking. Embedding the clusters makes the platinum more negatively charged, which repels ethylene, minimizing a critical pathway that leads to coking. The studies provide microscopic insight into the reduced coking in overcoated catalysts and offer a pathway toward reducing coking and sintering while maintaining the activity of the catalyst.

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Electronic effects in the coke deactivation of platinum-alumina catalysts

Cited by 2 publications

References 2 publications

Electronic density enrichment of Pt catalysts by coke in the propane dehydrogenation

Electronic density enrichment of Pt catalysts by coke in the propane dehydrogenation

Effect of Embedding Platinum Clusters in Alumina on Sintering, Coking, and Activity

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