表面增强拉曼光谱研究吸附电位对CO在Pt电极上氧化行为的影响  

Effect of Adsorption Potential on CO Oxidation at Au@Pt Nanoparticles Electrodes, A Surface Enhanced Raman Spectroscopic Study

作　　者：张普[1] 卫怡[1] 郑勇力[1] 陈艳霞[1] 田中群[2] 

机构地区：[1]中国科技大学化学物理系合肥微尺度物质科学国家实验室(筹),安徽合肥230026 [2]厦门大学化学化工学院固体表面物理国家重点实验室,福建厦门361005

出　　处：《电化学》2015年第4期305-311,共7页Journal of Electrochemistry

基　　金：国家重大科学仪器设备开发专项(No.2011YQ03012416)资助

摘　　要：预吸附电势对CO在Pt上的氧化行为有重要影响.在电势低于0.3 V(vs.RHE)下,预吸附的CO单层在Pt电极上0.4 V就开始氧化,并会在0.6 V左右出现1个较小的氧化峰,即所谓的"氧化前峰",而在双电层电位区间饱和吸附的CO只有当电势正于0.6 V才氧化.作者利用电化学原位表面增强拉曼光谱结合循环伏安与电势阶跃法,研究了Au核Pt壳纳米粒子上CO的氧化前峰现象,并根据获得的电化学及SERS结果对氧化前峰的产生机理进行了探讨.实验结果表明,预吸附电位对CO的Raman光谱影响很小,与相应的电化学原位红外光谱研究类似.基于上述数据,作者讨论了CO氧化前峰产生的可能机理.The adsorption/oxidation of CO on the 55 nm Au@0.7 nm Pt nanoparticles electrode in both potentiodynamic and potentiostatic modes were investigated by surface enhanced Raman spectroscopy in a thin layer electrochemical flow cell under controlled mass transport, with the aim of clarifying the origin CO oxidation at lower electrode potentials （in current pre-wave re- gion of corresponding cyclic voltammograms）. Our results demonstrated that the CO oxidation kinetics differed significantly from the three kinds of different CO adsorption history, with almost no CO oxidation current in the pre-peak potential region after 0.35 VRHE CO adsorption with or without subsequent holding the potential at 0.06 VRHE for 30 min, compared to the significant CO oxida- tion current at lower potentials in both cyclic voltammograms and potentiostatic current transients after CO adsorption at 0.06 VRHE. In contrast, at the same reaction potential in the pre-wave region both during linear potential sweep and potential step experiments, differences in Raman spectra of saturated CO adlayer with CO adsorption potential of 0.06 VRHE and 0.35 VRHE were negligible. Pos- sible origins for the effect ofpre-adsorption potential on CO oxidation kinetics are discussed.

关 键 词：CO氧化 氧化前峰 表面增强拉曼 

分 类 号：O657.37[理学—分析化学] O646.54[理学—化学]