PVP-Stabilized Palladium Nanoparticles in Silica as Effective Catalysts for Hydrogenation Reactions

Abstract

Palladium nanoparticles stabilized by poly (N-vinyl-2-pyrrolidone) (PVP) can be synthesized by corresponding Pd(acac)2(acac = acetylacetonate) as precursor in methanol at 80°C for 2 h followed by reduction with NaBH4and immobilized onto SiO2prepared by sol-gel process under acidic conditions (HF or HCl). The PVP/Pd molar ratio is set to 6. The effect of the sol-gel catalyst on the silica morphology and texture and on Pd(0) content was investigated. The catalysts prepared (ca.2% Pd(0)/SiO2/HF andca.0,3% Pd(0)/SiO2/HCl) were characterized by TEM, FAAS, and SEM-EDS. Palladium nanoparticles supported in silica with a size 6.6 ± 1.4 nm were obtained. The catalytic activity was tested in hydrogenation of alkenes.

Ruthenium nanoparticle-intercalated montmorillonite clay for solvent-free alkene hydrogenation reaction

“…[16][17][18][19][20][21] Several hydrogenating reagents such as NiCl 2 -NaBH 4 , PdCl 2 -NaBH 4 polyethylene glycol (PEG)-CH 2 Cl 2 , CoCl 2 -NaBH 4 etc., have been tested as hydrogenation systems. [22] Along with toxicity, these systems also suffered with long reaction time, high catalyst loading, costly starting materials and tedious reaction protocol of these hydrogenating reagents.…”

“…Hydrogenation of alkenes is an important synthesis tool for achieving a diversity of biologically important molecules in good yields. [16][17][18][19][20][21] Several hydrogenating reagents, such as NiCl 2 -NaBH 4 , PdCl 2 -NaBH 4 , polyethylene glycol (PEG)-CH 2 Cl 2 , and CoCl 2 -NaBH 4 , have been tested as hydrogenation systems; 22 however, in addition to toxicity, these systems were characterized by long reaction times, high catalyst loadings, costly starting materials and tedious reaction protocols.…”

Nitrate uptake using mesoporous silica embedded with zero-valent palladium nanoparticles

“…This is based on their important role in controlling the nucleation and growth of PdNPs. 29,31,32 As mentioned above, the synthesis was carried out under H 2 to act as a reducing agent in forming elemental palladium nanoparticles. X-ray photoelectron spectroscopy (XPS) was performed to ascertain the oxidation state of the element in the nal sample.…”

“…Ruas et al utilized an alcohol reduction method to prepare a suspension of Pd(0) solution using Pd(acac) 2 as the metal precursor, and polyvinylpyrrolidone (PVP) as a stabilizer, with a particle size distribution at 5.8 AE 1.1 nm, which agrees with our nding. 29 In addition, using palladium(II) hexauoroacetylacetonate [Pd(hfac) 2 ] as precursor, the Pd crystallite sizes impregnated into SBA-15 range from 6.0 to 7.9 nm, and the post deposition required 3 to 8 hours under supercritical carbon dioxide (scCO 2 ). 30 The size of the PdNPs formed inside the channels is likely to vary with different precursors as well as the choice of solvent system.…”