多晶铂电极表面硫吸附物种的原位表面增强拉曼光谱研究(英文)  

In situ Surface-Enhanced Raman Scattering Spectroscopic Study of Sulfur Adsorption on Polycrystalline Platinum Electrode Surface

作　　者：In-Su Park YuYe J.Tong 

机构地区：[1]美国乔治敦大学化学系

出　　处：《电化学》2010年第3期255-262,共8页Journal of Electrochemistry

基　　金：supported by DOE (DE-FG02-07ER15895) USA

摘　　要：本工作首次报道了在酸性或碱性电解质中高粗糙度多晶铂电极表面硫物种的吸附、电氧化过程的原位表面增强拉曼光谱研究.分别在两种情况下采集了粗糙铂电极的表面增强拉曼光谱:(a)循环伏安处理后控制一定电位(0.2V)下;(b)逐步控制不同电位.酸性电解质条件下,两种情况均观察到位于300cm-1的Pt—S振动.Pt—S键较强,阻止了氢在铂电极表面的吸附,需多次循环伏安处理才能完全将表面吸附的硫去除.同时还观察到位于470cm-1处的少量多聚S物种(S8或者其他类型).这些多聚S物种仅仅微弱地键合在铂电极的表面,可以容易地除去.在碱性电解质中,同样也在(a)和(b)情况下观察到位于310cm-1的Pt—S振动吸收.本工作了获得了有关硫在粗糙多晶铂电极表面吸附和电氧化重要信息,证明了原位表面增强拉曼光谱在研究铂表面的适用性.The paper reports the first in situ surface enhanced Raman scattering （SERS） spectroelectrochemistry study of sulfur adsorption and electro-oxidation on highly roughened polycrystalline Pt surface in both acidic and basic supporting electrolytes. The SERS spectra were taken at a constant electrode potential after accumulative electro-oxidation CVs of the Pt electrode with pre-adsorbed sulfur species and at different electrode potentials that were varied stepwise of the Pt electrode immersed in sulfur-containing electrolytes without pre-adsorbed sulfur species. In both cases,a dominant vibrational band at 299 cm -1 in acidic electrolyte but at 310 cm-1 in basic electrolyte was observed,which was assigned to the Pt—S stretching vibration. The Pt—S bond appeared quite strong as evidenced by the total blockage of the Pt surface for hydrogen adsorption and the need of multiple electro-oxidation CVs to completely remove the adsorbed sulfur. Additionally,a small amount of poly sulfur species （S8 or other types） as represented by a minor peak at 470 cm-1 was also observed in the acidic but not in the basic electrolyte. These poly sulfur species only bound to the Pt surface weakly and could be removed easily. This work yielded important information on sulfur adsorption and electro-oxidation on roughened,polycrystalline platinum surfaces and demonstrated the applicability and usefulness of the in situ SERS spectroelechemistry in investigating the chemistry of sulfur adsorption/poisoning on platinum surfaces.

关 键 词：铂 硫 拉曼光谱 

分 类 号：O433.5[机械工程—光学工程]