Reproducibility issues resulting from particle growth solutions made with cetyltrimethylammonium bromide (CTAB) surfactant from different lots and product lines in a newly developed synthesis of monometallic palladium (Pd) tetrahexahedra (THH) nanoparticles are investigated via a multi-pronged approach. Time-resolved electrochemical measurements of solution potential, variation of chemical parameters in colloidal synthesis, and correlation to electrodeposition syntheses are used together to uncover the effects of the unknown contaminants on the chemical reducing environment during nanoparticle growth. Iodide—a known impurity in commercial CTAB—is identified as one of the required components for equalizing the reducing environment across multiple CTAB sources. However, an additional component—acetone—is critical to establishing the growth kinetics necessary to enable the reproducible synthesis of THH in each of the CTAB formulations. In one CTAB variety, the powdered surfactant contains too much acetone, and drying of the as-received surfactant and re-addition of solvent is necessary for successful Pd THH synthesis. The relevance of solvent impurities to the reducing environment in aqueous nanoparticle synthesis is confirmed via electrochemical measurement approaches and solvent addition experiments. This work highlights the utility of real-time electrochemical potential measurements as a tool for benchmarking of nanoparticle syntheses and troubleshooting of reproducibility issues. The results additionally emphasize the importance of considering organic solvent impurities in powdered commercial reagents as a possible shape-determining factor during shaped nanomaterials synthesis.

中文翻译：

---

通过电化学测量解决微量化学杂质对纳米颗粒生长动力学的影响

通过多管齐下的方法研究了在新开发的单金属钯 (Pd) 四六面体 (THH) 纳米颗粒合成中使用来自不同批次和产品线的十六烷基三甲基溴化铵 (CTAB) 表面活性剂制成的颗粒生长溶液所产生的重现性问题。溶液电位的时间分辨电化学测量、胶体合成中化学参数的变化以及与电沉积合成的相关性一起用于揭示纳米颗粒生长过程中未知污染物对化学还原环境的影响。碘化物（商业 CTAB 中的一种已知杂质）被认为是平衡多个 CTAB 源还原环境所需的成分之一。然而，另一种成分——丙酮——对于建立每种 CTAB 配方中 THH 的可重复合成所需的生长动力学至关重要。在一种 CTAB 品种中，粉末状表面活性剂含有过多的丙酮，为了成功合成 Pd THH，必须干燥原样表面活性剂并重新添加溶剂。通过电化学测量方法和溶剂添加实验证实了溶剂杂质与水性纳米颗粒合成中还原环境的相关性。这项工作强调了实时电化学电位测量作为纳米颗粒合成基准测试和重现性问题故障排除的工具的实用性。研究结果还强调了在成形纳米材料合成过程中考虑粉状商业试剂中的有机溶剂杂质作为可能的形状决定因素的重要性。