SURFACE-MEDIATED FORMATION OF GOLD PARTICLES IN BASIC METHANOL

Metal particles are generated via the spontaneous reduction of AuCl4- ions in basic, air-saturated methanolic solutions. Stable Au colloids are formed in the presence of several stabilizers. The plasmon band of the metal particles is shifted considerably at the initial stages of the reaction, and light scattering is detected during these shifts. Kinetic results indicate that the reduction process is strongly influenced by the nature of the surface that is in contact with the solutions. It is proposed that generation of small metal particles occurs mainly on surfaces that contain ionized surface OH groups and that colloidal particles are formed when small metal particles desorb from the surfaces.