Photocatalytic behavior of silver vanadates: Microemulsion synthesis and post-reaction characterization

Silver vanadates with light absorption properties in the visible region were successfully prepared by a low temperature pathway (not exceeding 110 °C) using an optimized microemulsion methodology. The resulting materials were evaluated as photocatalysts in Rhodamine B photodegradation and characterized before and after reaction. The silver vanadates displayed silver metallic nanoparticles decorating the surface. The as-prepared Ag3VO4 catalyst was the most active. Nevertheless, this silver vanadate suffered important changes during reaction. The initial structure evolves yielding a silver pyrovanadate, Ag4V2O7, with a concomitant increase of the number and size of the silver metallic nanoparticles. The synergy between these Ag0 particles and the photoactivity of the Ag4V2O7 phase seems responsible of the high photoactivity of this material.

► Silver vanadates were synthesized by microemulsion methodology not exceeding 110 °C.
► Silver metallic nanoparticles decorated the surface of the silver vanadates.
► The photocatalytic properties were studied upon visible light.
► The stability of catalysts was evaluated after reaction.
► We report a synergistic effect between Ag0 particles and silver vanadates.