The synthesis of silver nanoparticles supported by silica-alumina is presented. The innovative combination of microwave-plasma and fluidized bed technologies are employed to decompose and vaporize silver precursors, such as silver oxide or silver nitrate. The results show that silver vapors condense with a homogeneous distribution of nanosize particles over the support. These particles range from 3 to 50 nm in diameter, as measured using electron microscopy. They are in a non-oxidized state, as revealed with X-ray photoelectron spectroscopy. The material shows attractive physical and chemical properties due to the excellent dispersion of metallic particles. The nano-Ag/SiO2-Al2O3 metal-ceramic composite can specifically be used as either a catalyst because it is active in the hydrodesulphurization of dibenzothiophene or as an antibacterial sand-filter due to its bactericidal effect on E. coli. (C) 2011 Elsevier B.V. All rights reserved.