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-assenibly 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 O-2(center dot-) and CI0 acted as the main reactive species. The electronic interaction was systematically studied and confirmed by the photo-electrochemical measurements. (C) 2014 Elsevier Ltd. All rights reserved.