Tetrahedral UMOFNs/Ag3PO4 Core–Shell Photocatalysts for Enhanced Photocatalytic Activity under Visible Light

摘要

A new visible-light-responsive tetrahedral ultrathin metal–organic framework nanosheet (UMOFNs)/Ag3PO4 composite photocatalyst with a core–shell structure was readily synthesized by sonication in an organic solvent. Characterization methods for the photocatalyst included X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and UV–vis diffuse reflectance spectroscopy. The XRD patterns of the composite photocatalyst before and after visible-light irradiation demonstrated that trace amounts of Ag ions in the composite photocatalyst easily transformed into Ag nanoparticles, which play a role in promoting charge separation at the interface of a heterojunction. The UMOFNs/Ag3PO4 composite photocatalyst showed higher photocatalytic activity for the photodegradation of 2-chlorophenol (2-CP) under visible-light irradiation (>420 nm) than Ag3PO4. The complete degradation of 2-CP was achieved in 7 min using the tetrahedral UMOFNs/Ag3PO4 core–shell photocatalyst, and the apparent reaction rate was approximately 26 times higher than that of pure Ag3PO4. Further, a scavenger experiment showed h+ and O2?– were the major reactive species involved in the photocatalytic reaction system. This enhanced photocatalytic activity results from the efficient separation of photoinduced electron–hole pairs and the increase of interface area between Ag3PO4, UMOFNs, and the Ag nanoparticles.