The colloidal gold nanoparticles were prepared by reducing chloroauric acid with NaBH4 in the presence of polyvinyl pyrrolidone (PVP).The influences of the amount of NaBH4 and PVP,reaction temperature and the order of adding NaBH4 on the morphology,particle size and dispersion of the synthesized gold nanoparticles are discussed.The gold nanoparticles' morphology and particle size distribution were characterized by transmission electron microscopy and UV-Vis spectroscopy.The results show that the optimized processing parameters for preparing gold nanoparticles with an average diameter of 4.3nm were worked out,the molar ratio of NaBH4 to chloroauric acid is 3.75∶1; the mass ratio of PVP to chloroauric acid is 1∶1; the reaction temperature is 100℃ ; the NaBH4 is added after chloroauric acid.The ways of influencing factors were explained and the reasons were analyzed.%以聚乙烯吡咯烷酮(PVP)为保护剂,用硼氢化钠还原氯金酸制备出金纳米颗粒,研究了还原剂和保护剂用量、反应温度及试剂加入顺序对金纳米颗粒粒径、形貌、分散性的影响.利用透射电子显微镜和紫外分光光度计对纳米金颗粒的形貌、分散性及尺寸进行表征.结果表明:采用硼氢化钠为还原剂时,硼氢化钠与氯金酸的摩尔比为3.75∶1,PVP与氯金酸的质量比为1∶1,反应温度为100℃并且在氯金酸和PVP的混合溶液中迅速加入硼氢化钠制备的金纳米颗粒均一、平均粒径在4.3nm、分散性好.同时研究了各个影响因素的作用方式并分析了原因.
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