Surface-Enhanced Raman Study of Cyanide Adsorption at the Platinum Surface

A detailed surface Raman study of the effect of the bulk concentration of cyanide (CN - ), electrode potential. and immersion potential on the adsorption behavior of CN - on the Pt electrode surface was performed on a confocal microprobe Raman system. The notable change of the C−N frequency and the Pt−C intensity at ca. −0.7 V (vs SCE) indicates a subtle change of the adsorption behavior of CN - on the platinum electrode in solutions with concentration of about 10 -4 M or lower. The concentration of cyanide in the bulk solution affects the adsorption behavior. The surface Raman signal can still be observed at concentrations as low as 10 -6 M. When the CN - concentration is higher than 10 -3 M, the potential for immersing the platinum electrode in the CN - solution has a remarkable effect on the adsorption behavior of CN - . With the high-quality surface Raman spectra, the surface enhancement factor for the adsorbed CN - was estimated to be about 150.