Preparation of ultrafine palladium particles on cationic and anionic clays, mediated by oppositely charged surfactants: Catalytic probes in hydrogenations

Z. Király, B. Veisz, A. Mastalir, Gy Köfaragó

Research output: Contribution to journalArticle

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Abstract

Finely divided Pd particles (2-3 nm in diameter) were synthesized by the reduction of Pd2+ precursor ions in the presence of cationic (myristyltrimethylammonium bromide, MTA+Br-) or anionic (sodium dodecyl sulfate, Na+DS-) surfactants. The protective adsorption layer of the ionic surfactants around the particles ensured the long-term stability of the aqueous dispersions. When the palladium hydrosol stabilized with MTA+Br- was mixed with an aqueous suspension of sodium montmorillonite, Na+MM- (a cationic clay), the cation-exchange reaction between Na+ and MTA+ rendered the montmorillonite surface hydrophobic, in parallel with the incorporation of the released Pd particles into the MTA+MM- organoclay host. In a similar way, after addition of the palladium hydrosol stabilized with Na+DS- to an aqueous suspension of hydrotalcite nitrate, HT+NO3- (an anionic clay), the ion exchange between NO3- and DS- resulted in the formation of a hydrophobic clay, HT+DS-, with simultaneous deposition of the released Pd particles onto the clay lamellae. The low-loaded, highly dispersed Pd-organoclay materials displayed extremely high catalytic activities under mild conditions in the liquid-phase hydrogenations of styrene, hex-1-ene, and cyclohexene. Furthermore, the catalysts exhibited high selectivities for the partial hydrogenation of 1-phenyl-1-pentyne to 1-phenyl-cis-1-pentene. These high activities and selectivities were explained in terms of the high degree of dispersion of the Pd particles and the hydrophobic nature of the catalysts.

Original languageEnglish
Pages (from-to)5381-5387
Number of pages7
JournalLangmuir
Volume17
Issue number17
DOIs
Publication statusPublished - Aug 21 2001

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Pemetrexed
Palladium
Surface-Active Agents
clays
Hydrogenation
hydrogenation
palladium
Clay
Surface active agents
surfactants
Bentonite
Organoclay
preparation
hydrotalcite
probes
Clay minerals
Ion exchange
montmorillonite
Suspensions
Catalysts

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Preparation of ultrafine palladium particles on cationic and anionic clays, mediated by oppositely charged surfactants : Catalytic probes in hydrogenations. / Király, Z.; Veisz, B.; Mastalir, A.; Köfaragó, Gy.

In: Langmuir, Vol. 17, No. 17, 21.08.2001, p. 5381-5387.

Research output: Contribution to journalArticle

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