Herein, we describe an experimental approach for adapting the principles of Raman spectroelectrochemistry to electrodes controlled using a bipolar circuit. This method allows the simultaneous acquisition of spectroscopic data as a function of both the electrode potential and the chemical composition of a bimetallic alloy and can be generalized to other system variables. The electrochemical reduction of 4‐nitrothiophenol (4‐NTP) was carried out on bimetallic Ag/Au alloy gradients and monitored in situ using a confocal Raman microscope with 785 nm excitation. Continuous Ag/Au alloy gradients, in which the alloy composition varied from approximately 0.5 to 1.0 mole fraction Ag, were prepared by using bipolar electrodeposition and then modified with a monolayer of 4‐NTP using self‐assembly. 4‐NTP monolayers on Au/Ag alloys were placed in a bipolar electrochemical cell and characterized as a function of applied potential and chemical composition by using surface‐enhanced Raman scattering. The E_1/2 for NTP reduction was observed to be a strong function of the alloy composition, increasing by over 100 mV as the mole fraction of Ag varied from 0.5 to 1.0. In addition, spectroscopic evidence for the formation of the partially reduced intermediate, 4,4’‐dimercaptoazobenzene (DMAB) at intermediate applied potentials, was also found. Bipolar Raman spectroelectrochemistry (BRSE) is a powerful tool for acquiring in situ multidimensional Raman spectroelectrochemical data.

中文翻译：

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双极拉曼光谱电化学研究在Ag / Au双金属合金表面还原4-硝基硫酚

在这里，我们描述了一种将拉曼光谱电化学原理适应于使用双极性电路控制的电极的实验方法。该方法允许同时获取光谱数据，该数据是双金属合金的电极电势和化学成分的函数，并且可以推广到其他系统变量。在双金属Ag / Au合金梯度上进行4-硝基硫酚（4-NTP）的电化学还原，并使用共聚焦拉曼显微镜在785 nm激发下现场监测。通过使用双极电沉积制备连续的Ag / Au合金梯度，其中合金成分从大约0.5到1.0摩尔分数的Ag，然后通过自组装用4-NTP单层改性。将Au / Ag合金上的4-NTP单层放置在双极电化学池中，并通过使用表面增强拉曼散射将其作为施加电势和化学成分的函数。的观察到用于NTP还原的E _1/2是合金成分的强大功能，当Ag的摩尔分数从0.5变为1.0时，其增加了100 mV以上。此外，还发现了在中间施加电势下部分还原的中间体4,4'-二巯基偶氮苯（DMAB）形成的光谱证据。双极拉曼光谱电化学（BRSE）是用于获取原位多维拉曼光谱电化学数据的强大工具。