Ag/ZnO photocatalyst for photodegradation of methylene blue

Abstract

Ag/ZnO photocatalysts have been prepared through a coprecipitation method with different Ag loadings. The photocatalysts were characterized by XRD, SEM, XRF, and DRS UV-vis methods. The Ag loadings (1.7-4.4%) slightly decrease the ZnO crystal size from 27.9 to 25.6 nm. There is no effect of Ag loadings on the morphology of photocatalysts that have clustered spherical shape. The Diffuse Reflectance spectra showed the pure ZnO and Ag/ZnO photocatalysts have no significant difference in absorption in UV region, but rised of Ag loading increase the absorption in visible region. Photodegradation of 20 ppm methylene blue (MB) solution was used to evaluate the performance of Ag/ZnO photocatalysts on UV, visible and dark and was compared to pure ZnO. Loading Ag (1.7%) can enhance the photocatalytic activity of photocatalyst, however the excessive of Ag concentration (3.4 and 4.4%) on photocatalysts tend to decrease of photocatalytic activity.