Characterization of interfacial behaviour of ortho-positioned diaryl disulfide on silver substrates by surface-enhanced Raman scattering and electroreduction

Highlights: • Interfacial behaviour of ortho-positioned diaryl disulfide on silver was characterized. • Probe molecule at pH 11.5 was used to estimate Raman enhancement factor of silver. • EF constructed from DA-modified Ag was about 1.98 × 10⁵. • Method offers novel assessments for Raman enhancement and electrocatalytic activity. -- Abstract: The interfacial behaviour of ortho-positioned diaryl disulfide on activated silver substrates was characterized with surface-enhanced Raman scattering and electroreduction. After the fracture of the disulfide bond, the diaryl disulfides interacted with Ag to form self-assembled monolayers. The peak intensity of benzene ring deformation and pH-dependence presented two types of linear relationships. The probe molecule at pH 11.5 was used to estimate the Raman enhancement factor of silver substrates. Also, the alkaline media were favorable for the active intermediates of ortho-positioned diaryl disulfide to interact on the liquid-solid silver interfaces. Linear regression fitting between the reciprocals of surface coverage and those of solution concentration from reductive desorption was observed, and meaningful progress of spectroelectrochemical mechanisms was made for surface chemistry.