Ag-Ag3VO4/AgIO3 composites with enhanced visible-light-driven catalytic activity.

Ag-Ag3VO4/AgIO3 composites composed of Ag-Ag3VO4 particles (major component) and AgIO3 nanosheets (minor component) were obtained via photoreduction of Ag3VO4/AgIO3 composites prepared by sequential precipitation. The optimal Ag-Ag3VO4/AgIO3 catalysts (in particular, the one with an AgIO3/Ag3VO4 mass ratio of 6.4%) were found to be more active than AgIO3, Ag3VO4, and Ag-Ag3VO4 in the photocatalytic degradation of rhodamine B (RhB), methylene blue (MB), methyl orange (MO), and tetracycline hydrochloride (TC) under visible-light irradiation. Ag-Ag3VO4/AgIO3 can be reused in cycling experiments. Photogenerated holes (h+) and superoxide radical anions (O2-) were demonstrated by radical-capture experiments as the main active species in the photocatalytic degradation of RhB. The more efficient separation and transfer of photogenerated electron-hole pairs are responsible for the enhanced activity of Ag-Ag3VO4/AgIO3. A possible photocatalytic mechanism is proposed.