Study of surface catalytic photochemical reaction by using conventional and Fourier transform surface enhanced Raman scattering

Conventional and Fourier transform (FT) surface-enhanced Raman scattering (SERS) from 4-aminophenyl disulfide (APDS) adsorbed on HNO3-etched silver foils was investigated. After visible laser irradiation, new bands appeared near 1435, 1390 and 1145 cm−1, which were assigned, respectively, to stretching modes of NN and φN bonds of azo compounds, indicating that the amino groups of APDS had reacted. The same effect was observed when measuring the roughened APDS adsorbed silver foil by using the near infrared (NIR) laser either for long time scanning, or after exposing silver foil to the light with main wavelength of 365 nm for some time. No reaction was observed for solid APDS and the smooth APDS adsorbed silver foil under similar conditions. It was suggested that the SERS substrates with nanometer grade roughness may play a surface catalytic role in the interaction between APDS and the substrates under the laser irradiation.