Effect of Adsorption Potential on CO Oxidation at Au@Pt Nanoparticles Electrodes, A Surface Enhanced Raman Spectroscopic Study
- 2015年第21卷 
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 region 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 oxidation 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. Possible origins for the effect of pre-adsorption potential on CO oxidation kinetics are discussed.