Reaction of p-chloronitrobenzene adsorbed on silver nanoparticles

Surface-enhanced Raman spectroscopy (SERS) on silver nanoparticles is highly sensitive because of surface plasmon resonance. We have studied the structures and photoinduced chemical reactions of p-chloronitrobenzene (PCNB) molecules adsorbed on silver nanoparticles using a combination of SERS and density functional theory (DFT) calculations. When the PCNB molecules are adsorbed to the surface of silver nanoparticles in alkaline solution, the SERS spectra are very different from the normal Raman spectra of PCNB. Comparison of the DFT simulated Raman spectra of PCNB and p,p'- dichloroazobenzene (DCAB) indicates that the new peaks in the SERS spectrum of PCNB adsorbed on silver nanoparticles arise from the azo (C-N=N-C) group of DCAB.