CO和SCN~-在高分散Pt及Pd表面异常红外光学行为的电化学现场FTIR反射光谱研究

在玻碳基底上沉积Pt和Pd，在以CO和SCN-为探针分子的电化学现场FTIR反射光谱研究中，首次观察到异常红外光学行为，其中包括吸附物种的谱带方向倒反以及谱峰强度显著增强等．

In situ FTIR Spectroscopic Investigations of Abnormal Infrared Properties of Absorption of CO and SCN~- on Dispersed Pt and Pd Surfaces

The in situ molecular-probe FTIR spectroscopy was employed in the present workto study the adsorption of CO and SCN- on surfaces of dispersed Pt and Pd thin layers,which were deposited electrochemically on glassy carbon (denoted as Pt/GC and Pd/GC)uner voltanmmetric conditions. Abnormal IR features of adsorption of CO and SCN- andPt/GC and Pd/GC have been observed for the first time. In comparison with IR features ofadsorption of these molecules on smooth Pt and Pd electrodes, the abnormal IR featuresconsist of mainly the inversion of the direction of IR band and the enhancement of bandintensities. The enhancement factors were evaluated at 20 for linearly bonded CO on the Pt/GCsurface anal at 26 for bridge bonded CO on the Pd/GC surface. Nevertheless other spectralfeatures(the vibrational frequency, the Stark effects, etc. ) are nearly the same as thoseobserved on smooth Pt and Pd electrodes, and no significant difference in IR features presentedfor adsorption of solution species (CO2, SCN- ) on the dispersed surfaces. The surfaceroughness of these dispersed electrodes was measured relatively small (1.6 for Pt/GC and 1.2for Pd/GC). The present study discovered an interesting IR property of dispersed metallicthin layers, and suggested that the in situ iR spectra of larger signal to noise ration may beobtained by employing the specially prepared Pt/GC and Pd/GC electrodes.