铂金
拉曼光谱
带材弯曲
电化学
吸附
拉曼散射
化学
过渡金属
金属
无机化学
氢键
极化率
电极
分子
分析化学(期刊)
材料科学
物理化学
催化作用
光学
物理
生物化学
光电子学
有机化学
色谱法
作者
Jian‐Feng Li,Yifan Huang,Sai Duan,Ran Pang,De‐Yin Wu,Bin Ren,Xin Xu,Zhong‐Qun Tian
摘要
The observed surface-enhanced Raman scattering (SERS) spectra of water adsorbed on metal film electrodes of silver, gold, and platinum nanoparticles were used to infer interfacial water structures on the basis of the change of the electrochemical vibrational Stark tuning rates and the relative Raman intensity of the stretching and bending modes. To explain the increase of the relative Raman intensity ratio of the bending and stretching vibrations at the very negative potential region, density functional theory calculations provide the conceptual model. The specific enhancement effect for the bending mode was closely associated with the water adsorption structure in a hydrogen bonded configuration through its H-end binding to surface sites with large polarizability due to strong cathodic polarization. The present results allow us to propose that interfacial water molecules exist on these metal cathodes with different hydrogen bonding interactions, i.e., the HO–H⋯H–Pt dihydrogen bond for platinum and the HO–H⋯Ag(Au) for silver and gold. This dihydrogen bonding configuration on platinum is further supported from observation of the Pt–H stretching band. Furthermore, the influences of the pH effect on SERS intensity and vibrational Stark effect on the gold electrode indicate that the O–H stretching SERS signals are enhanced in the alkaline solutions because of the hydrated hydroxide surface species adsorbed on the gold cathode.
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