N-甲基咪唑与2,2'-联吡啶在铜表面共吸附的SERS研究

采用电化学现场表面增强拉曼光谱(SERS)分别研究了非水体系中N-甲基咪唑(NMIM),2,2’-联吡啶(2,2-’bipy)在铜电极表面的吸附行为以及两者的共吸附行为。结果表明在非水体系中,NMIM可在很宽的电位区间内稳定地吸附在金属表面,而2,2-’bipy在一个相对较窄的电位区间内能稳定地吸附在金属表面。当两者共存时存在竞争吸附和共吸附行为,较负的电位下主要以NMIM吸附为主,在略偏负的电位区间内以2,2-’bipy吸附为主,而正电位区间两者在金属表面共吸附,NMIM倾斜吸附在金属表面,而2,2’-bipy以顺式结构垂直吸附在金属表面。

Surface Enhanced Raman Spectroscopic Studies on the Coadsorption of N-Methylimidazole and 2,2'-Bipyridine at Cu Electrode

The adsorption behavior and coadsorption of N-methylimidazole(NMIM) and 2,2'-bipyridine(2,2'-bipy) at copper electrode were investigated by in situ electrochemical surface enhanced Raman spectroscopy(SERS) in the acetonitrile solution.In situ SERS studies revealed that NMIM can adsorb stably onto Cu electrode in a quite different potential range,but the potential range for adsorbing 2,2'-bipy is narrow.With the introduction of 2,2'-bipy into the solution,the SERS could be divided into three parts:(a) under-0.8 V,NMIM molecule adsorption,(b) near the open potential,2,2'-bipy molecule adsorption with cis-conformation,(c) at positive potential region,both NMIM and 2,2'-bipy were coadsorbed at Cu surface,and the SERS data also suggested that the NMIM bound to copper surface with a tilted orientation,while the 2,2'-bipy was adsorbed through cis-conformation to the surface.