Xu Jian-Fang, Luo Shi-Yi, Liu Guo-Kun
Department of Physics, School of Physics and Mechanical & Electrical Engineering, Xiamen University, Xiamen 361005, China.
State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 May 15;143:35-9. doi: 10.1016/j.saa.2015.02.039. Epub 2015 Feb 14.
In order to explore the key role of surface plasmon resonance (SPR) and active (3)O2 for the chemical transformation to 4,4-dimercaptoazobenzene (DMAB) from p-aminothiophenol (PATP) adsorbed on Ag or Au NPs, we systematically investigated the laser wavelength and temperature dependent surface-enhanced Raman spectra of PATP capped Ag and Au NPs. DMAB can be easily observed at the 514.5nm laser for Ag NPs but at the 632.8nm laser for Au NPs, indicating that a suitable energy level is necessary for the formation of DMAB. The tendency is consistent with the wavelength dependent SPR properties of Ag or Au NPs accordingly. With the energy provided by annealing, the transformation of PATP to DMAB is much easier on Ag NPs at a lower temperature, and more DMAB can be observed at the same temperature, compared to the case of Au NPs under the same condition. It is mainly due to the active (3)O2 on Ag surfaces could be more easily formed than that on Au surfaces.
为了探究表面等离子体共振（SPR）和活性（3）O2对吸附在Ag或Au纳米颗粒上的对氨基硫酚（PATP）化学转化为4,4-二巯基偶氮苯（DMAB）的关键作用，我们系统地研究了PATP包覆的Ag和Au纳米颗粒的激光波长和温度依赖的表面增强拉曼光谱。对于Ag纳米颗粒，在514.5nm激光下很容易观察到DMAB，而对于Au纳米颗粒，在632.8nm激光下才能观察到，这表明形成DMAB需要合适的能级。相应地，这种趋势与Ag或Au纳米颗粒的波长依赖SPR特性一致。在退火提供的能量作用下，与相同条件下的Au纳米颗粒相比，在较低温度下，PATP在Ag纳米颗粒上更容易转化为DMAB，并且在相同温度下可以观察到更多的DMAB。这主要是因为Ag表面比Au表面更容易形成活性（3）O2。
