Plasmon enhanced visible light photocatalytic activity of ternary Ag2Mo2O7@AgBr–Ag rod-like heterostructures

Abstract

In this work, a three-component system, Ag₂Mo₂O₇@AgBr–Ag, has been successfully prepared through an in situ ion exchange reaction between Ag₂Mo₂O₇ rods and Br⁻, followed by visible light irradiation. Using the as-prepared samples as photocatalysts, the visible light photocatalytic activity for degrading organic dyes, including methylene blue (MB) and Rhodamine B (RhB), is examined systematically. Among Ag₂Mo₂O₇, Ag₂Mo₂O₇/Ag, Ag₂Mo₂O₇@AgBr, AgBr–Ag and Ag₂Mo₂O₇@AgBr–Ag, the three-component Ag₂Mo₂O₇@AgBr–Ag heterostructured photocatalyst is demonstrated to be superior compared to the others for dye photodegradation. The enhancements in visible light absorption and photocatalytic activity are ascribed to the synergistic effects originating from the surface plasmon resonance (SPR) of the Ag nanoparticles (NPs) and the cascade energy transfer for the effective separation of photogenerated carriers. Radical-trapping experiments demonstrate that holes (h⁺) are the major reactive species accounting for the degradation of MB and RhB molecules. Furthermore, five cycle tests indicate that the three-component hybrid photocatalyst Ag₂Mo₂O₇@AgBr–Ag is highly stable and can be used repeatedly. Therefore, the Ag₂Mo₂O₇@AgBr–Ag ternary heterostructures may be a promising candidate for use as a visible light photocatalyst for degrading organic contaminants in the near future.