Surface Raman spectroscopic studies on the adsorption of pyridine at bare iron electrodes

Surface-enhanced Raman spectroscopic (SERS) studies have been extended succ essfully to iron electrodes by using a highly sensitive confocal microprobe Raman system. Several surface roughening procedures were attempted to obta in high-quality surface Raman spectra of pyridine on iron electrodes. Resul ts show that proper surface roughness factor can not only increase the surf ace area, but also induce a weak SERS effect. Potential-dependent surface R aman spectra of pyridine in neutral solution suggest that the pyridine mole cule may be adsorbed onto the iron electrode through the nitrogen atom by a coordination bond of Fe-N in an end-on configuration (or slightly tilting) . Decreasing the solution pH value to ca. 2.0 did not affect the adsorption of pyridine and the pyridinium ion may dissociate before its adsorption on to the iron surface. (C) 2001 Published by Elsevier Science B.V.