In situ synthesis of plasmonic Ag@AgI/TiO2 nanocomposites with enhanced visible photocatalytic performance

Abstract In this work, plasmonic ternary Ag@AgI/TiO2 nanocomposites were prepared by an in situ two-step photoreduction synthesis method. The nanocomposites were investigated using XRD, SEM, TEM-EDX, SAED, XPS, and UV–visible spectroscopy. The photocatalytic activity and stability of Ag@AgI/TiO2 in RhB (Rhodamine B) degradation were quantified using measurements under visible light conditions. The results demonstrate that Ag@AgI/TiO2 exhibits good photocatalytic performance for the degradation of RhB. And that specifically the composite photocatalyst 0.2Ag@AgI/TiO2 shows the best photocatalytic performance. For this composition, the photocatalytic degradation rate was 91% at 90 min, with a reaction rate constant of 0.00997 min-1, the largest of the group studied here. This rate is 1.57 times higher than Ag@AgI, and 14 times higher than the minimum value for TiO2. A radical capture experiment confirmed that the dominant active species of Ag@AgI/TiO2 composites in the process of RhB degradation are O·- 2 (superoxide anions) and h+ (holes). The experimental date provides a basis for inferring the photocatalytic degradation mechanism of RhB by Ag@AgI/TiO2.