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.
田莉
,
李君涛
,
叶进裕
,
甄春花
,
孙世刚
. 吸附态和溶液相CO在Pt(110)电极上氧化过程的CV和in situ FTIRS 研究[J]. 电化学, 2010
, 16(3)
: 285
-289
.
DOI: 10.61558/2993-074X.3357
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. 200 mV 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. 05 V.
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