New method of synthesis of silver nanoparticles

Silver nanoparticles were prepared by reducing AgNO/sub 3/ with sodium hypophosphite in water-in-oil microemulsions in the presence of a mixture of ethoxylated alkylphenols as a surface-active substance (SAS). Ag/SAS/Al/sub 2/O/sub 3/ materials containing 0.04-0.13 wt% Ag were prepared by applying the microemulsions to an Al/sub 2/O/sub 3/ support and studied by diffuse reflection electronic spectroscopy, small-angle X-ray scattering, and X-ray diffraction. Ag particles in Ag/SAS/Al/sub 2/O/sub 3/ materials have a mean size of 70 W. The absorption band at 385 nm in the electronic spectra indicates that the nanoparticles consist of isolated clusters.