Time-Resolved Near-Infrared Surface-Enhanced Raman Spectroscopy of a Surface-Confined Electrochemical Reaction of 9,10-Phenanthrenequinone

A measurement system for time-resolved surface-enhanced Raman spectroscopy with a submillisecond time resolution was developed using a step-scan near-infrared Fourier-transform spectrometer and was applied to analyze a redox reaction of 9,10-phenanthrenequinone (PQ) adsorbed on a polycrystalline gold electrode. In the time-resolved surface-enhanced Raman spectra, both quinone and hydroquinone forms of PQ were recognized, but the intermediate species, semiquinone radicals, were not. It was suggested that the lifetime of the intermedeate species was shorter than 0.5 ms, which was the time resolution of the developed system.