Mechanistic Study of Continuous Reactive Aromatic Organothiol Adsorption onto Silver Nanoparticles

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• 作者：Siyam M. Ansar ; Ganganath S. Perera ; Patricia Gomez ; George Salomon ; Erick S. Vasquez ; I-Wei Chu ; Shengli Zou ; Charles U. Pittman ; Jr. ; Keisha B. Walters ; Dongmao Zhang
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：December 27, 2013
• 年：2013
• 卷：117
• 期：51
• 页码：27146-27154
• 全文大小：460K
• ISSN：1932-7455

文摘

Organothiol (R-SH) (OT) adsorption onto silver nanoparticles (AgNPs) in water was studied for a series of aromatic OTs including p-methylbenzenethiol (p-MBT), p-benzenedithiol (p-BDT), and 2-mercaptobenzimidazole (2-MBI). Unlike the common view that OT forms monolayer adsorption on AgNPs, we found that these aromatic OTs continuously reacted with AgNPs through formation of RS鈥揂g complexes until complete OT or AgNP consumption occurred. The RS鈥揂g complex can remain on the AgNP surface, converting the AgNPs into core鈥搒hell structures. The OT adsorption onto AgNPs occurs predominately through reaction with silver oxide present on the AgNP surfaces before the OT addition or formed from environmental oxygen in the presence of OT. The RS鈥揌 protons are completely released when both p-MBT and 2-MBI reacted with AgNP, Ag₂O, and AgNO₃. However, a substantial fraction of S鈥揌 bonds remained intact when p-BDT, the only dithiol used in this work, is adsorbed on AgNPs or reacted independently with Ag₂O and AgNO₃. The new insights from this work should be important for understanding OT interaction with AgNPs in water and the SERS spectra of the OT adsorbed onto AgNPs.