Abstract This paper presents a new model for predicting the evolution of the particle size of gold nanoparticles (GNPs) in the citrate synthesis method. In this method, the precursor is an acid solution of tetrachloroauric acid, while the reducing agent is a base solution of sodium citrate. The acid-base properties of the solutions influence how the size of the particles evolves during the synthesis. In the literature, various mechanistic theories have been proposed to explain this evolution. Turkevich et al. (1951), who pioneered this synthesis method, suggested the “organizer theory”. This mechanistic description of the synthesis was modelled by Kumar et al. (2007), but recently Agunloye et al. (2017) showed that in several cases this model performed poorly, since it does not account for the acid-base properties of the reactants. In this work, we present a kinetic model based on the synthesis seed-mediated mechanistic description proposed by Wuithschick et al. (2015). In this description, the precursor concurrently reduces into gold atoms and hydroxylates into a passive form. The gold atoms then aggregate into seed particles, which finally react with the passive form of the precursor in a growth step. We validated the model using experimental data from the literature obtained for conditions in which the seed-mediated mechanism is valid. The predicted GNP final sizes closely agree with those obtained experimentally.

中文翻译：

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柠檬酸盐合成法中金纳米颗粒的形成模型

摘要 本文提出了一种预测柠檬酸盐合成方法中金纳米粒子 (GNP) 粒径演变的新模型。在该方法中，前体是四氯金酸的酸溶液，而还原剂是柠檬酸钠的碱溶液。溶液的酸碱性质会影响合成过程中颗粒大小的变化。在文献中，已经提出了各种机械理论来解释这种演变。图尔克维奇等人。(1951) 开创了这种合成方法，提出了“组织者理论”。这种合成的机械描述是由 Kumar 等人建模的。(2007)，但最近 Agunloye 等人。(2017) 表明，在一些情况下，该模型表现不佳，因为它没有考虑反应物的酸碱特性。在这项工作中，我们提出了一个基于 Wuithschick 等人提出的合成种子介导机制描述的动力学模型。(2015)。在该描述中，前体同时还原为金原子和羟基化为被动形式。然后金原子聚集成种子颗粒，最终在生长步骤中与被动形式的前体反应。我们使用从在种子介导机制有效的条件下获得的文献中获得的实验数据验证了该模型。预测的 GNP 最终大小与实验获得的结果非常一致。然后金原子聚集成种子颗粒，最终在生长步骤中与被动形式的前体反应。我们使用从在种子介导机制有效的条件下获得的文献中获得的实验数据验证了该模型。预测的 GNP 最终大小与实验获得的结果非常一致。然后金原子聚集成种子颗粒，最终在生长步骤中与被动形式的前体反应。我们使用从在种子介导机制有效的条件下获得的文献中获得的实验数据验证了该模型。预测的 GNP 最终大小与实验获得的结果非常一致。