title: PdNP Decoration of Halloysite Lumen via Selective Grafting of Ionic Liquid onto the Aluminol Surfaces and Catalytic Application.
abstract: The synthesis of selectively deposited palladium nanoparticles (PdNPs) inside tubular halloysite lumens is reported. This specific localization was directed by the selective modification of the aluminol surfaces of the clay mineral through stable Al-O-C bonds. An ionic liquid (1-(2-hydroxyethyl)-3-methylimidazolium) was grafted onto halloysite following the guest displacement method (generally used for kaolinite) using halloysite-DMSO preintercalate. The characterization of this clay nanohybrid material (XRD, NMR, TGA) showed characteristics reminiscent of similar materials synthesized from kaolinite. The grafting on halloysite lumens was also effective without using the DMSO preintercalate. The presence of these new functionalities in halloysite directs the synthesis of uniform PdNPs with size ranging between 3 and 6 nm located exclusively in the lumens. This results from the selective adsorption of PdNPs precursors in functionalized lumens through an anion exchange mechanism followed by in situ reduction. In contrast, the unmodified clay mineral displayed nanoparticles both inside and outside the tubes. These catalysts showed significant catalytic activity for the reduction of 4-nitrophenol (4-NP). The most efficient catalysts were recycled up to three times without reducing significantly the catalytic activities.
authors.affiliation: Center for Catalysis Research and Innovation and Department of Chemistry and Biomolecular Sciences, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada.|Laboratory of Analytical Chemistry, Faculty of Science, University of Yaounde I , B.P. 812, Yaounde, Cameroon.
authors.forename: Gustave K
authors.initials: GK
authors.lastname: Dedzo
authors.affiliation: Center for Catalysis Research and Innovation and Department of Chemistry and Biomolecular Sciences, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Ngnie
authors.affiliation: Center for Catalysis Research and Innovation and Department of Chemistry and Biomolecular Sciences, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Detellier
keywords: 4-nitrophenol; catalysis; grafting; halloysite; intercalation; nanotubes; palladium nanoparticles