超声场下金胶体的制备及其紫外-可见吸收光谱研究

Research on Preparation and UV-vis Absorption Spectrum of Au Colloids under the Ultrasonic Field

摘要:

在超声场作用下，以氯金酸为前驱物， PVP为保护剂，经KBH4还原，制备了分散均匀的金胶体。利用X射线衍射、透射电子显微镜和分光光度技术等对制备的金胶体进行了表征。结果表明：金纳米粒子为25 nm左右的球形或椭球形。还原剂用量对金胶体的最大吸收峰位影响较大，当KBH4用量小于1 mL时，最大吸收波长为530 nm，吸收峰较低而宽；KBH4加入量超过2 mL时，最大吸收峰明显蓝移，在512~514 nm，最大吸收峰增强，但峰变宽。继续增加KBH4用量超过5 mL，吸光度曲线基本不变，KBH4用量超过8 mL后最大吸收峰在510 nm左右，但吸光度较高，且峰形尖而窄，单分散性好。超声场分布、超声功率和温度使金胶体的最大吸收峰变小，最大吸收峰位在510 nm左右。

Abstract:

Well-dispersed Au colloids were prepared from AuCl3 and KBH4 under the protection of polyvinylpyrrolidone (PVP) in the ultrasonic field. The Au colloids were characterized by means of transmission electron microscope (TEM), X-ray diffraction (XRD) and spectrophotometer. The results indicate that Au nanoparticles are spherical or axiolitic and the grain diameter is about 25 nm. The reductant dosage has a great effect on the UV-vis absorption spectrum of Au colloids. When the dosage of KBH4 is lower than 1 mL, the maximum absorption peak is in 530 nm and the peak is low and broad. When the dosage of KBH4 is over 2 mL, the maximum absorption peak has a large blue shift to 512 -514 nm. The peak is strong and broad. When the dosage of KBH4 is over 5 mL, the absorbency graphs are alike. When the dosage of KBH4 is over 8 mL the maximum absorption peaks are in 510 nm around. The peak is strong, sharp and narrow, so the Au colloids are well-dispersed. The ultrasonic field distribution, power and temperature have a great effect on the absorbency graphs of Au colloids. The peaks are weak and the maximum peaks are in 510 nm around.