Pd(0) Nanoparticle Stabilized by Tannin-grafted SiO2 Beads and Its Application in Liquid-hydrogenation of Unsaturated Organic Compounds

Abstract

Heterogeneous Pd(0) catalysts were synthesized using bayberry tannin-grafted silica beads (BT-SiO 2 ) as the supports, in which bayberry tannin acts as a stabilizer to prevent Pd(0) nanoparticles from aggregation as well as an antioxidant for keeping Pd(0) nanoparticles from oxidation. The main physical and chemical properties of the catalysts were characterized by Ultraviolet diffusion reflection spectra, X-ray diffraction, Transmission microscopy, and X-ray photoelectron spectroscopy. Experimental results indicated that Pd(0) nanoparticles stabilized by BT-SiO 2 were highly active, selective and reusable in liquid-hydrogenation of unsaturated organic compounds.

Hydroxylated surface of GaAs as a scaffold for a heterogeneous Pd catalyst

“…This implies that solid-supported palladium catalysts serve as reservoirs of catalytically active species to effect the C-C bond formations homogeneously. Hence, it is desirable to develop a suitable scaffold that has a moderate affinity for Pd(0) nanoparticles 27,[15][16][17][18][19][20][21] and is strong enough to retain and stabilize them without aggregation, but weak enough to release them slowly.…”

Development of a new palladium catalyst supported on phenolic resin

“…Huang et al reported that silica gel functionalized with bayberry tannin was an excellent support for maintaining catalytic activity over long time periods because the tannin stabilized the Pd nanoparticles. 3 As well as this, Funaoka's group demonstrated that the addition of lignophenols increased the discharge capacity of a batteries because they prevent the suppression of Pb particle growth. 4 The common feature of these two studies is that the addition of naturally occurring polyphenols is effective for the stabilization of metal nanoparticles.…”

Hydrogen (H2) sensing and catalysis with organic-stabilized Pd and Pd alloy nanoparticles.

“…152 In the case of the homogeneous 12x C16NH 2 Pd and PdAg NP catalysts, the selectivity to the alcohol was 60% which is lower than that of the commercial hydrogenation catalysts with high surface area, such as Pd/C 130,139 and Pd/Al 2 O 3 (~75%). 136,152 However, these NP catalysts exhibited higher activity (TOF = 700-1000), with C16NH 2 Pd 91 Ag 9 NPs being the best, compared to the activity of other homogeneous systems previously investigated including Pd and Pt NPs stabilized by dendrimers 30,123 and alkanethiolate monolayers (TOF < 500).…”

“…Catalytic selective hydrogenation of allyl alcohol to produce 1-propanol, which is a precursor in organic synthesis and the pharmaceutical industry, has been studied as a function of particle size and shape of Pd NPs coated with polymers, 134,135 biopolymers (collagen fiber), 136 surfactants, 35 or dendrimers 29,30,32,123,124,137,138 either in solution or immobilized on solid supports such as alumina, 35,134 composites, 32 silica, 139 and magnetic NP cores. [140][141][142] However, the transformation of allyl alcohol to carbonyl compounds (isomerization reaction) has not been widely explored using Pd NPs as catalysts.…”

“…Because this allyl alcohol is the simplest α,β-unsaturated alcohol and has been used as a substrate in prior studies, 29,30,32,35,123,124,[134][135][136][137][138][139][140][141][142] it was a good starting point for this work.…”