Electrosynthesis of powdery silver particles can be effectively carried out with an H2O-oleic acid or an H2O-glycerol mix solvent (volume ratio 1∶1 ) as the electrolytic medium and AgNO3 as the supporting electrolyte.Experimental results indicate that the presence or absence of the surfactant sodium dodecyl sulfate (SDS) and the choice of electrolytic medium have a significant impact on the shape and size of the prepared Ag particles.With H2O-glycerol as the electrolytic medium,spherical Ag nanoparticles can be obtained in the presence of SDS (0.6g/L),while an Ag sample electrodeposited without SDS has a dendritic microcrystalline structure.For the reduction of methyl orange (MO) and methylene blue (MB) with NaBH4 as the reducing agent,the spherical Ag nanoparticles exhibit much better catalytic activity than the dendritic Ag microparticles.Further investigations show that surface modification by an oleic acid medium could greatly improve the catalytic activity of the electrodeposited Ag particles for the reduction of MO and MB.