Radiation-induced reduction of mixed silver and rhodium ionic aqueous solution

Silver and rhodium metal nanoparticles were synthesized by electron beam and T-radiolysis of mixed solutions containing (Rh-II acetate) dimer and Ag+ sulfate in variable proportions. From the observation of the optical absorption spectra, transmission electron microscopic images and local X-ray analysis at increasing doses, it is concluded that the metals are segregated into two populations, which are randomly distributed according to the mixture content, one of 1.5-2 nm pure rhodium clusters, and the other of 15-20 nm pure silver clusters. At complete reduction of both metals, the Ag nanoparticles are systematically surrounded by the small rhodium. clusters. (C) 2002 Elsevier Science Ltd. All rights reserved.