Intense electrochemical sers signal following hydrogen evolution

Stepping the potential of the electrode to the region of rapid hydrogen evolution prior to performing an oxidation—reduction cycle (ORC) can result in the development of surface-enhanced Raman scattering that is more intense by almost an order of magnitude than an electrode subjected to ORC alone. It is found for the case of chloride adsorbed on silver that the spectral characteristics of the metal-surface—chloride stretching mode at ≈240 cm^?1 are essentially the same as that produced without prior hydrogen evolution. The additional enhancement appears to be due to morphological changes caused by the presence of hydrogen bubbles during the reduction of the silver-chloride phase film.