Abstract
Colloids of metallic gold were prepared by ultrasonic irradiation of Na[AuCl_4] (Au(III)) with 1-propanol in aqueous solutions under various experimental conditions; i. e., the distances between reactor and oscillator, the temperature of solution and the output power. The rate of colloid formation was investigated with TEM and UV-vis specrtroscopic observation. The rate of reduction remarkably depended on the irradiation conditions. The maximum rate of Au(III) reduction was recognized at 20℃. The rate, furthermore, increased with increasing the output power of ultrasonic oscillator. The particle size of Au colloids obtained in the present sonochemical reduction was observed to be considerably small in comparison with conventional method with H_2 in gas phase. The average size of Au particle gradually increased with decreasing the rate of reduction, which controlled by the temperature of solution and by the distance between the reactor and oscillator.
