Evidence for Surface Ag Complex Formation by an AnionInduced Effect in the SER Spectra of Phthalazine Adsorbed on Silver Sols

Raman, surface-enhanced Raman scattering and DFT study of para-nitro-aniline

“…3 where the MEP of pNA is depicted, the most negative regions of MEP are associated with the nitro group. This fact, corroborated with the positively induced Ag charged particles due to the chlorine anions chemisorbed onto the colloidal surface [18,19] suggest the most probable adsorption of pNA to the silver colloid through the nitro group. However, as seen in Fig.…”

SERS of Dithiocarbamate Pesticides Adsorbed on Silver Surface; Thiram

“…Studies by Pettinger, Roy, Furtak, Fleischman, and Watanabe have shown that an electrochemically roughened silver electrode presents a surface containing Ag + ions that are stabilized by coadsorbed Cl − ion, a constituent of the electrolyte. 28 The roles of stabilizing Cl − ions or other coadsorbed species on a positively charged Ag ion have been predicted and then experimentally verified. First of all, we are going to investigate the influence of surface Cl − ions on the SER spectra of thiram.…”

SERS effect from silver photoreduced on to silica colloidal nanoparticles

“…19 Otherwise, in Ag hydrosol with co-adsorbed chloride anions, no evidence of photoreaction was detected by SERS, which closely resembled the Raman spectrum of the corresponding Ag(I) coordination compound. 18 Also in the Ag-doped silica colloid the SERS bands related to the photoproduct were almost absent (Fig. 2), owing to the presence of chloride anions in the solution.…”

“…The SERS of phthalazine in salt-free Ag colloids 18 showed the occurrence of some weak bands observed at 484, 507, 755, 1539 cm 1 , which with difficulty matched the normal Raman spectrum of the free ligand. This feature was successfully interpreted as being due to a photoreaction, involving the cleavage of the N-N bond of phthalazine.…”

“…Moreover, the chloride anions, which are present in the silica dispersion, are able to co-adsorb and further increase the Raman enhancement of the ligands. 18 In order to confirm the formation of surface layers of silver on the silica particles during the laser irradiation and to understand better the enhancement mechanism, a transmission electron microscopy investigation will be performed and reported in a forthcoming paper. Finally, higher stability of the Ag-doped silica suspensions, with respect to the hydrosols constituted by pure silver, is ensured by a slight aggregation of the colloidal particles after addition of ligands.…”