Studies of oxidation Processes of Adsorbed and Solution CO on Pt(110) Electrode by Cyclic Voltammetry and in situ FTIRS

通讯作者，Tel:(86-592)2181081， E-mail:sgsun@xmu．edu.cn[中文文摘]应用电化学原位傅里叶变换红外反射光谱(in situ FTIRS)研究了酸性介质中Pt(110)单晶电极上吸附态CO(COad)和溶液相CO(COsol)的氧化过程.循环伏安测试表明,COsol氧化的峰电位比COad氧化的正移了168mV,其峰电流密度为后者的6.7倍.电化学原位红外光谱检测到CO主要生成线型的吸附态物种(COL),均匀分布在Pt(110)表面上.当溶液中不存在CO时,COL仅在电位高于0.15V才发生氧化.而且,该谱峰在其稳定吸附的电位区间内随电位增加蓝移,Stark系数为30cm-1·V-1;在COL发生氧化的电位区间,其谱峰强度随电位增加减小、峰位红移,线性变化率为-56cm-1·V-1.溶液中饱和CO时,原位红外光谱在-0.05V即可检测到CO2的存在,显示COL起始氧化的电位提前了200mV;电位高于-0.05V,该谱峰即发生红移,对应的线性变化率为-26.5cm-1·V-1.[英文文摘]The oxidation processes of adsorbed CO (COad) and solution phase CO (COsol) on Pt(110) electrode were investigated by cyclic voltammetry and in-situ FTIR spectroscopy. It has revealed that in comparison with COad on Pt(110) in a CO-free solution,the oxidation current peak of COsol in a CO-saturated solution is positively shifted ca. 168 mV,and the peak current density has been increased by 6.70 times. Linear adsorbed CO (COL)is determined by in-situ FTIR spectroscopy as the main species,which is uniformly distributed on Pt (110) surface． In a CO-free solution， the onset potential of COL is measured by in-situ FTIRS ca．0． 15 V; the COL band is blue-shifted with the increase of electrode potential in the potential range where COL is stable，yielding a Stark tuning rate 30 cm － 1·V － 1 ; when the COL is oxidized at E ＞ 0．15 V，the COL band is red-shifted at a rate of － 56 cm － 1·V － 1 ． In the case of CO-saturated solution， the CO2 band could be appeared in the in-situ FTIR spectrum recorded at － 0．05 V，demonstrating that the onset potential of COL oxidation is negatively shifted ca． 200mV in comparison with Pt(110) in a CO-free solution; the COL band is immediately red-shifted with a rate of－26．5 cm－1·V－1 when the potential is above －0．5 V．国家自然科学基金项目(20833005,20828005,20921120405)资