Autocatalytic Oxidization of Nanosilver and Its Application to Spectral Analysis

The stable yellow nanosilver (AgNP) and blue nanosilver (AgNPB) sols were prepared by the NaBH(4) procedure. The new nanocatalytic reaction of AgNP-NaCl-H(2)O(2) was investigated by surface plasmon resonance (SPR) absorption, resonance Rayleigh scattering (RRS), surface-enhanced Raman scattering (SERS) and scanning electron microscope (SEM) techniques. The autocatalytic oxidization of Ag on AgNP surface by H(2)O(2) was observed firstly and the AgNP/AgCl nanoparticles were characterized. The [Ag(+)] from AgNP is different to the Ag(+) from AgNO(3) that adsorb on the AgNP surface. An autocatalytic oxidization mechanism was proposed to explain experimental phenomena. The relationship between the SPR absorption peaks and the RRS peaks of AgNPB was studied, and three characteristic RRS peaks called as out-of-plane quadrupole, out-of-plane dipole and in-plane dipole RRS peaks were observed firstly. Using AgNP as nanoprobe, a simple, sensitive and selective RRS method was developed for assay of H(2)O(2) in the range of 2.0 × 10(−8)-8.0 × 10(−5) mol/L.