Synthesis and catalytic application of palladium nanoparticles supported on kaolinite-based nanohybrid materials

Abstract

Palladium nanoparticles (PdNPs) were deposited on the surface of the modified clay mineral, kaolinite. To improve compatibility, abundance and control of the size of the nanoparticles, kaolinite was modified by the grafting of an amino alcohol (triethanolamine (TEA)) and an ionic liquid (1-(2-hydroxyethyl)-3-methylimidazolium (ImIL)). Characterization techniques (XRD, TGA, solid state (13)C NMR and FTIR spectroscopy) confirmed the effective grafting of these compounds on the internal surface of kaolinite. After the synthesis of PdNPs onto clay particles, TEM allowed the visualization of abundant PdNPs with sizes ranging from 4 to 6 nm, uniformly distributed onto the platelets of modified kaolinite. Unmodified clay showed low abundance and random distribution of the nanoparticles. The catalysts obtained were effective for the catalytic reduction of 4-nitrophenol (4-NP), the material with TEA being the most effective. These materials have exhibited excellent performance during the Heck and particularly the Suzuki-Miyaura coupling reactions, with reaction yields up to 100%. These catalysts showed a very slight loss in activity for three consecutive catalytic cycles (less than 10% decrease of the activity compared to the first cycle). This was an evidence that the prior grafting modification of kaolinite helps in significantly improving the quality of the synthesized NPs and also promotes their strong attachment onto the clay mineral surface.

A magnetically-separable H 3 PW 12 O 40 @Fe 3 O 4 /EN-MIL-101 catalyst for the one-pot solventless synthesis of 2H-indazolo[2,1- b ] phthalazine-triones

“…Critical design parameters for nanocomposite catalysts include ease of fabrication, separation and recycle and on-stream stability, which together influence their suitability for the large-scale commercial production of bulk and speciality chemicals and pharmaceuticals [5][6][7]. Of the many naturally occurring and synthetic catalytic materials available, metal-organic frameworks (MOFs) have risen in prominence for applications in organic synthesis due to their tunable microporosity (and more recently micro/mesoporosity [8]), extremely high surface areas, and wide range of pre-and post-synthetic routes to incorporate different chemical functionality [9][10][11].…”

Functional Kaolinite

“…The grafting was decisive to ensure the presence of abundant NPs with narrow and specific sizes. These catalysts were found to be efficient for the catalytic reduction of 4‐nitrophenol . The interlayer kaolinite surfaces were reacted with ethanolamine in order to functionalize the interlayer space with an iron‐porphyrin derivative which proved to be an efficient catalyst for oxidation reactions .…”

Kaolinite Clay Mineral Reactivity Improvement through Ionic Liquid Functionalization

“…The presence of the grafted organic cation of the IL was decisive for the good dispersion and the control of the size of the metal nanoparticles. The obtained catalysts were found to be very efficient during the Heck and particularly the Suzuki‐Miyaura coupling reactions . The catalyst was also successfully used for hydrogen evolution reaction in acidic electrolytic solution…”

“…The obtained catalysts were found to be very efficient during the Heck and particularly the Suzuki-Miyaura coupling reactions. [68] The catalyst was also successfully used for hydrogen evolution reaction in acidic electrolytic solution. [69] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56…”