Comparative Study of the Adsorption of Thiol and Isocyanide Molecules on a Silver Surface by in Situ Surface-Enhanced Raman Scattering
Comparative Study of the Adsorption of Thiol and Isocyanide Molecules on a Silver Surface by in Situ Surface-Enhanced Raman Scattering
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DOI：
10.1021/acs.jpcc.9b05383
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发表时间：
2019-09-05
影响因子：
3.7
通讯作者：
Qin, Dong
中科院分区：
文献类型：
--
作者：
Ahn, Jaewan;Shi, Shi;Qin, Dong
我们报告了通过表面增强拉曼散射（Sers）研究硫醇和异氰化物分子在胶体银纳米立方体上的吸附。具体来说，我们收集Sers光谱原位在不同的时间点从银纳米立方体和配体分子的混合物在特定的浓度。我们证明，4-硝基苯硫酚可以很容易地结合到银表面通过强烈的巯基-银相互作用。我们还观察到随着浓度的降低，Sers峰的红移，这表明相对于表面的分子取向的变化。同样，4-氨基苯硫酚也能快速吸附到银上，但由于给电子的胺基会阻碍Sers的化学增强，因此相对于4-硝基苯硫酚，4-氨基苯硫酚的Sers信号要弱得多。与硫醇不同，1，4-亚苯基二异氰酸酯通过相对较弱的s-供体键与Ag表面结合。随着浓度的增加，分子倾向于吸附在纳米立方体上，苯环倾斜远离表面。我们进一步研究了硫醇和异氰化物的竞争性结合，证明了硫醇抑制异氰化物吸附的能力，当这两个配体存在于混合物中时。
We report an investigation of the adsorption of thiol and isocyanide molecules on colloidal Ag nanocubes through surface-enhanced Raman scattering (SERS). Specifically, we collect SERS spectra in situ at different time points from a mixture of Ag nanocubes and ligand molecules at a specific concentration. We demonstrate that 4-nitrothiophenol could readily bind to the Ag surface through strong thiol-Ag interaction. We also observe red shifts for the SERS peaks as the concentration decreases, suggesting a change to the molecular orientation relative to the surface. Likewise, 4-aminothiophenol also adsorbs onto Ag quickly, but gives much weaker SERS signals relative to 4-nitrothiophenol because the electron-donating amine group would retard the chemical enhancement of SERS. Different from thiols, 1,4-phenylene diisocyanide binds to Ag surface through a relatively weak, s-donation bond. With an increase in concentration, molecules tend to adsorb on the nanocubes with the benzene ring tilting away from the surface. We further investigate the competitive binding of thiol and isocyanide, demonstrating the capability of thiol to inhibit the adsorption of isocyanide when these two ligands are presented in a mixture.