Direct observation of p,p′-dimercaptoazobenzene produced from p-aminothiophenol and p-nitrothiophenol on Cu₂O nanoparticles by surface-enhanced Raman spectroscopy

Surface-enhanced Raman scattering of p-aminothiophenol and p-nitrothiophenol were obtained on the surface of Cu₂O nanoparticles, showing novel spectral changes with morphology-dependent and time-dependent characteristics. The measured Raman signals were believed to partly originate from the newly produced surface species p,p′-dimercaptoazobenzene. The nature of surface chemisorption status during Raman measurement was investigated experimentally and theoretically via combined surface-enhanced Raman scattering and density functional theory study, indicating that surface catalytic reaction of p-aminothiophenol and p-nitrothiophenol could take place on the surface of oxide nanostructures as well as coinage metal material.