Green synthesis of Ag/ZnO microplates by doping Ag ions on basic zinc carbonate for fast photocatalytic degradation of dyes.

The Ag/ZnO microplates, composed by various nanoparticles, were facilely synthesized by calcination of the precursor obtained by ion exchanging between zinc carbonate hydroxide [Zn2(OH)2CO3] and silver nitrate (AgNO3) in a short time. The structures of ZnO and Ag/ZnO were characterized carefully by a series of methods and so on. Especially, the results from the UV-Vis-NIR diffuse reflectance and PL spectra confirmed that the presence of metallic Ag led to the fact that the adsorption of visible light and an increase of separation of electrons and holes in the Ag/ZnO composite. The photocatalytic activities of the Ag/ZnO were 1.5 and nearly 5 times higher that of ZnO for removal of RhB and MB, respectively. We proposed a possible mechanism to explain the enhanced photocatalytic degradation over Ag/ZnO under UV light irradiation. Finally, this work could provide a simple example for the synthesis of metal-semiconductor composite as well as their applications.