Photocatalytic degradation of dye by Ag/ZnO prepared by reduction of Tollen's reagent and the ecotoxicity of degraded products.

A heterostructure of Ag/ZnO powder was prepd. by a redn. of Ag(NH3)2+ ions in a basic soln. or Tollen's reagent. From this method, the existence of a metallic Ag coating on the ZnO surface was confirmed by transmission electron microscope and XPS. The photocatalytic activity of the Ag/ZnO powders was investigated by analyzing the degrdn. of an aq. methylene blue soln. under a blacklight irradn. Furthermore, the parameters, including Ag content, catalyst loading, initial dye concn. and pH, were also studied. After the methylene blue soln. was irradiated for 30min under a blacklight illumination, total mineralization was not obsd. as the presence of some carbon compd. species was indicated in a mass spectrum. Furthermore, the toxicity of the treated methylene blue soln. produced by the Ag/ZnO powders was also investigated by a test for the inhibition of the growth of Chlorella vulgaris. [on SciFinder(R)]