An oil-in-water self-assembly synthesis, characterization and photocatalytic properties of nano Ag@AgCl surface-sensitized K₂Ti₄O₉

Highlights: • The plasmatic Ag@AgCl surface-sensitized K₂Ti₄O₉ composite photocatalysts. • Ag@AgCl greatly increased visible light absorption for K₂Ti₄O₉. • The photocatalysts exhibited enhanced photocatalytic dye degradation. - Abstract: Nano-sized plasmonic Ag@AgCl surface-sensitized K₂Ti₄O₉ composite photocatalysts (hereafter designated as Ag@AgCl/K₂Ti₄O₉) was synthesized via a facile oil-in-water self-assembly method. The photocatalytic activity of the prepared materials for RhB (Rhodamine B) degradation was examined under visible light irradiation. The results reveal that the size of Ag@AgCl, which evenly dispersed on the surface of K₂Ti₄O₉, distributes about 20–50 nm. The UV–vis diffuse reflectance spectra indicate that Ag@AgCl/K₂Ti₄O₉ samples have a significantly enhanced optical absorption in 380–700 nm. The photocatalytic activities of the Ag@AgCl/K₂Ti₄O₉ samples increase first and then decrease with increasing amount of loading Ag@AgCl and the Ag@AgCl(20 wt.%)/K₂Ti₄O₉ sample exhibits the best photocatalytic activity and 94.47% RhB was degraded after irradiation for 2 h. Additionally, studies performed using radical scavengers indicated that O₂·⁻ and Cl⁰ acted as the main reactive species. The electronic interaction was systematically studied and confirmed by the photo-electrochemical measurements