SURFACE-CHEMISTRY OF COLLOIDAL GOLD - DEPOSITION AND REOXIDATION OF PB, CD, AND TL

Abstract

AbstractLead, cadmium and thallium are deposited on colloidal gold particles in aqueous solution. The deposition occurs through the reduction of the metal ions by excess electrons which are donated to the gold particles by free organic radicals generated radiolytically. The absorption spectra of the composite particles are measured and compared to calculated ones (using Mie theory and the optical constants of the pure metals). — Au‐Pb particles are stable and well separated, and there is reasonable agreement between experimental and calculated spectra. Reoxidation of the lead mantle by Ag+ ions leads to a silver mantle, although about 5% of the deposited lead is not oxidized; this is attribu..