Ligand Desorption and Desulfurization on Silver Nanoparticles Using Sodium Borohydride in Water

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• 作者：Ganganath S. Perera ; Siyam M. Ansar ; Shanshan Hu ; Maodu Chen ; Shengli Zou ; Charles U. Pittman ; Jr. ; Dongmao Zhang
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：May 15, 2014
• 年：2014
• 卷：118
• 期：19
• 页码：10509-10518
• 全文大小：548K
• 年卷期：v.118,no.19(May 15, 2014)
• ISSN：1932-7455

文摘

We recently reported that a wide range of ligands, including organothiols (OTs), can be completely desorbed from gold nanoparticles (AuNPs) by NaBH₄ in water. In addition, NaBH₄ induces desulfurization of 2-mercaptobenzimidazole (2-MBI) and 6-thioguanine (6-TG) on AuNPs. Reported herein is a systematic investigation of treating ligands adsorbed onto silver nanoparticles (AgNPs) with NaBH₄. These results are compared and contrasted to those previously reported for the same set of ligands adsorbed onto AuNPs. Complete desorptions from AgNPs by NaBH₄ in water were observed for nonspecifically adsorbed ligands that include Rhodamine 6G, adenine, thiophene, and halides (Cl^{鈥?/sup>, Br鈥?/sup>, and I鈥?/sup>). These cleaned AgNPs can be reused for surface-enhanced Raman spectroscopy acquisition. However, OT ligands could not be completely desorbed from AgNPs regardless of the amount of NaBH₄ used in this work. NaBH₄ can induce complete 6-TG desulfurization adsorbed on AgNPs, but the desulfurization rate is significantly slower than that on AuNPs. Transmission electron microscope analysis revealed that NaBH₄ induced more extensive nanoparticle fusion for AgNPs than for AuNPs. A mechanistic study indicates that AgNPs serve as electron transfer hubs for hydrides in BH₄鈥?/sup> to protons in water. In addition to providing new insights for AgNP recycle, reuse, and catalytic applications, this work also highlights the significant differences in the structure and properties of OTs adsorbed on AuNPs and AgNPs.}