In situ Surface-Enhanced Raman Spectroscopic Investigation of Formaldehyde Oxidation on Aucore@Ptshell Nanoparticles Coated Platinum Electrode in Different Media

Au-core@Pt-shell nanoparticles were synthesized by chemical reduction method. The samples were characterized by scanning electron microscope( SEM ) and energy dispersive spectroscopy ( EDS ). In situ surface-enhanced Raman spectroscopy( SERS ) was utilized to investigate the electro-oxidation behavior of formaldehyde in different media adsorbed on Au-core@Pt-shell nanoparticles coated platinum electrode. Surface-enhanced Raman scattering spectra with high quality were acquired. The results show that formaldehyde can dissociate spontaneously to produce strongly adsorbed intermediate, CO, in acidic, neutral, and alkaline media on a Au-core@Pt-shell nanoparticles coated platinum electrode. However, the bridge adsorbed CO were increased more significantly in alkaline media. In addition, the bridge adsorbed CO could be oxidized more easily than the linear adsorbed CO. The Raman signal of CO disappeared at -0. 4 V in alkaline media, it shifted negatively about 950 mV than in acidic or neutral media. The study demonstrates that Au-core@Pt-shell nanoparticles coated on platinum substrate as electrode exhibited better electrocatalytic properties for the oxidation of formaldehyde in alkaline media than in acidic or neutral media.