• Korean Journal of Materials Research
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• v.13 no.5
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• pp.285-291
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• 2003

The nanosized silver and gold particles are prepared by ERC method in which metal vapors with high temperature is rapidly quenched by coolants such as liquid nitrogen or liquid argon. In order to monitor the crystal structural changes on the internal and the surface of the nanosized noble metal particles, lattice parameter, internal strain and Debye-Waller factor are investigated, and the calculation of X-ray diffraction scattering intensity is performed. The lattice parameters of silver and gold particles agree with those of bulk materials, and crystal internal strain of the metal particles is not changed by rapid cooling. The Debye-Waller factor of gold particles is increased with decreasing particle size because of the surface softening phenomenon of nanosized particles, but the crystal structural change on the surface of the particles is not detected from the comparison the calculated X-ray diffraction profile with the experimental profile on gold particles with the particle size of 4 nm.

• Elastomers and Composites
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• v.50 no.4
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• pp.274-278
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• 2015

Nanosized gold particles were synthesized by microwave irradiation in a mixture composed of potassium tetrachloroaurate(III) n-hydrate, sodium citrate dihydrate and Tween 20. The synthesized gold particles were characterized by UV-vis spectrophotometer, scanning electron microscopy, and X-ray diffraction techniques. Using UV-vis spectroscopy, it was confirmed that gold nanoparticles act as a catalyst in the reduction of 4-nitroaniline with sodium borohydride to form 1,4-diaminobenzene. Additionally, we studied the kinetics of this reductive reaction in the presence of these gold nanoparticles under various conditions.