Synthesis and photocatalytic performance of an efficient Ag@AgBr/K2Ti4O9 composite photocatalyst under visible light

•The plasmatic Ag@AgBr sensitized K2Ti4O9 composite photocatalysts.•Ag@AgBr greatly increased visible light absorption for K2Ti4O9.•The plamonic photocatalysts exhibited enhanced activity for the degradation of RhB.

Ag@AgBr nanoparticle-sensitized K2Ti4O9 composite photocatalysts (Ag@AgBr/K2Ti4O9) were prepared by a facile precipitation–photoreduction method. The photocatalytic activities of the Ag@AgBr/K2Ti4O9 nanocomposites were evaluated for photocatalytic degradation of (RhB) under visible light irradiation. The composites exhibited excellent visible light absorption, which was attributable to the surface plasmon effect of Ag nanoparticles. The Ag@AgBr was uniformly scattered on the surface of K2Ti4O9 and possessed sizes in the range of 20–50 nm. The loading amount of Ag@AgBr was also studied, and was found to influence the absorption spectra of the resulting composites. Approximately 95.9% of RhB was degraded by Ag@AgBr (20 wt.%)/K2Ti4O9 after irradiation for 1 h. The stability of the material was also investigated by performing consecutive runs. Additionally, studies performed using radical scavengers indicated that O2− and Br0 acted as the main reactive species. Based on the experimental results, a photocatalytic mechanism for organics degradation over Ag@AgBr/K2Ti4O9 photocatalysts was proposed.

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