الفهرس 
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Abstract
Palladium nanoparticles stabilized by polyethylene glycol (PEG) were synthesized by two different methods: chemical reduction and hydrothermal. The Pd/PEG catalyst was fully characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier Transform Infrared (FT-IR), Ultra violet-visible (UV-vis) spectroscopy and N2 adsorption-desorption isotherm. XRD results indicated the poor crystalline state of as-synthesized Pd catalysts and TEM images revealed that the spherical Pd nanoparticles with average particle size of 5 nm are well dispersed in PEG matrix. Both the surface area and the particle size are influenced by the (Pd acetate: PEG) molar ratio, molecular weight of PEG, reduction temperature, reaction time and palladium precursor.
In the simple reduction method, Pd nanoparticles were prepared by using PEG and Pd(OAc)2 in the absence of other chemical agents. PEG appeared to act as both reducing agent and stabilizer. The optimum conditions that achieved from this method are: Pd acetate: PEG weight percent 3.75 %, molecular weight of PEG 4000, operating temperature 75°C and reaction time 2 hours.