Broad-Band Sum-Frequency Generation Spectroscopy at Platinum/Solution Interfaces

Vibrational Broad-Band Sum-Frequency Generation Spectroscopy (BB-SFG) is the second-generation SFG method for studying surfaces, including wet electrochemical interfaces.~ BB-SFG measurements, which are based upon the second-order nonlinear optical process are inherently interface specific (as is SFG) but add sensitivity and control to SFG.~~ The electrochemical cell used for the reported measurements has an ideal configuration where the thickness of the supporting electrolyte (25 $\mu $m) is controlled by a spacer, allowing for rapid spectral acquisitions (5 s$^{-1})$ synchronized with the potential sweep at 5 mV s$^{-1})$.~ In the talk, simultaneous electrochemical and BB-SFG measurements will be reported for adsorption/oxidation of carbon monoxide on polycrystalline and well-ordered Pt(hkl) electrodes with both CO-free and CO-saturated electrolytes.~ The emphasis will be on the combination between thin layer electrochemistry (TLE) and vibrational electrode surface analysis, and on dynamics of Pt/solution interfaces probed by the CO molecule adsorption and oxidation.