Evidence for seed-mediated nucleation in the chemical reduction of gold salts to gold nanoparticles
Evidence for seed-mediated nucleation in the chemical reduction of gold salts to gold nanoparticles
复制标题
DOI：
10.1021/cm000662n
复制
发表时间：
2001-07-01
影响因子：
8.6
通讯作者：
Murphy, CJ
中科院分区：
文献类型：
--
作者：
Jana, NR;Gearheart, L;Murphy, CJ
纳米粒子的种子介导生长概念的核心是，小的纳米粒子种子作为成核中心，使纳米粒子生长到所需的尺寸。我们通过透射电子显微镜和电子吸收光谱，在一个模型体系——通过还原金盐湿化学合成金纳米粒子中检验了这一常见假设。我们发现改变种子浓度确实会影响产物纳米粒子的尺寸，但试剂添加方法对结果的影响甚至更大。对于快速添加还原剂的情况，种子的存在似乎促进了更多种子的形成而非生长。与粒子生长相比，观察到的成核现象显著增强（99%）。对于缓慢添加还原剂的情况，种子确实会生长，但产物纳米粒子形状的均匀程度会受到影响。对于较高的种子浓度，与快速添加还原剂相比，缓慢添加还原剂时纳米粒子的生长能得到更好的控制。我们提出了一个机制步骤来解释常见的尺寸分布。
Central to the concept of seed-mediated growth of nanoparticles is that small nanoparticle seeds serve as nucleation centers to grow nanoparticles to st desired size. We have examined this common assumption in a model system, the wet chemical synthesis of gold nanoparticles via reduction of a gold salt, by transmission electron microscopy and electronic absorption spectroscopy. We find that changing the seed concentration does affect the size of the product nanoparticles, but the method of reagent addition drastically affects the outcome even more. For fast addition of reducing agent, the presence of seeds appears to promote the formation of more seeds instead of growth. The observed nucleations are drastically enhanced (99%) compared to particle growth. For slow addition of reducing agent, the seeds do grow, but the product nanoparticle's degree of homogeneity in shape is compromised. For higher concentrations of seeds, nanoparticle growth is better controlled for slow addition of reducing agent compared to fast addition of reducing agent. We propose a mechanistic step to explain the commonly observed size distribution.