Nanoparticles‐on‐electrode approach for in situ surface‐enhanced Raman spectroscopy studies with platinum‐group metals: examples and prospects

Abstract

AbstractSurface‐enhanced Raman spectroscopy (SERS) spectra have been obtained for different species (CO, CN−, ethylene and oxalic acid) adsorbed on nanostructured electrodes prepared by deposition of Pt, Pd, Rh and Pd:Pt nanoparticles on either gold or platinum electrodes. These examples not only refer to stable adlayers of typical adsorbates, such as carbon monoxide and cyanide, but also to adsorbates that may be easily either reduced or oxidized at some of these metals, such as ethylene and oxalic acid. On the other hand, the SERS spectrum of CO adsorbed on a transition metal alloy (Pd/Pt = 1) electrode is obtained for the first time. Taking advantage of the high surface enhancement factor found for these nanostructured samples (∼550 for CN− on Pt at − 0.4 V/SCE), ethylene and oxalic SER spectra are obtained for pure platinum electrodes. The importance of the charge‐transfer mechanism for the enhancement in the case of Pt is evidenced according to the ratio of the band intensities for CO or CN− to the oxalic ones. Specific advantages of the nanoparticles‐on‐electrode approach are highlighted. Copyright © 2005 John Wiley & Sons, Ltd.