Carbon accumulation, deactivation and reactivation of Pt catalysts upon exposure to hydrocarbons

Zoltán Paál, Attila Wootsch, Robert Schlögl, Ute Wild

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The formation and catalytic effect of carbonaceous deposits was studied on monofunctional Pt catalysts: Pt black (PtN, i.e., reduced with hydrazine), Pt/SiO2 (EUROPT-1), Pt on "herringbone" graphite nanofiber (Pt/GNF-H, GNF being able to store hydrogen) and Pt/CeO2 (ceria tending to consume spilt over hydrogen). They were exposed to hexane or t,t-hexa-2,4-diene between 483 and 663 K, with or without H2. Hydrocarbon transformations during these deactivating exposures as well as in subsequent standard test reaction with hexane in hydrogen excess were studied. Carbon accumulation on Pt black after analogous deactivating treatments was also examined by electron spectroscopy (XPS and UPS). The abundance of hydrogen on Pt sites controlled the activity and selectivity containing much Pt-C species. The amount of surface C could reach ∼45% causing almost total activity loss, but even ∼30% C on Pt blacks decreased markedly the catalytic activity, due to massive 3D deposits. "Disordered" carbon selectively poisoned the formation of saturated C6 products and fragmentation. The yield of dehydrogenation to hexenes was a good universal indicator of deactivation for each catalyst. Four regions were distinguished: "beneficial", "selective", "non-selective" and "severe" deactivation.

Original languageEnglish
Pages (from-to)135-145
Number of pages11
JournalApplied Catalysis A: General
Volume282
Issue number1-2
DOIs
Publication statusPublished - Mar 30 2005

Fingerprint

Hydrocarbons
Hydrogen
Carbon
Catalysts
hydrazine
Hexanes
Hexane
Deposits
Graphite
Electron spectroscopy
Cerium compounds
Hazardous materials spills
Dehydrogenation
Nanofibers
Hydrazine
Catalyst activity
X ray photoelectron spectroscopy

Keywords

  • Aromatization
  • Deactivation
  • Hexane
  • Hydrogen
  • Isomerization
  • Monofunctional Pt
  • Platinum black
  • Pt
  • UPS
  • XPS

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology

Cite this

Carbon accumulation, deactivation and reactivation of Pt catalysts upon exposure to hydrocarbons. / Paál, Zoltán; Wootsch, Attila; Schlögl, Robert; Wild, Ute.

In: Applied Catalysis A: General, Vol. 282, No. 1-2, 30.03.2005, p. 135-145.

Research output: Contribution to journalArticle

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