AgI/TiO2 was prepared using a dissolution-precipitation method, followed by calcination at different temperatures (100-700 degrees C). The as-prepared AgI/TiO2 powders were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis-DRS) and electrochemical impedance spectroscopy (EIS). The results revealed that calcination temperature significantly impacted the visible light absorption of AgI/TiO2 along with a shift from metastable gamma-AgI to relatively stable beta-AgI. We found that highest photocatalytic reduction rate of Cr(VI) and beta-Agl content were obtained for a calcination temperature of 350 degrees C. Furthermore, the pseudo first order rate constant was five times that for a photocatalyst calcined at 100 degrees C. The dramatically enhanced reduction rate of Cr(VI) was attributed to enhanced visible light absorption and greatly reduced charge transfer resistance, which eventually facilitates more efficient separation and easier transfer of photogenerated electron-hole pairs to the catalyst surface. Other experimental conditions were also carefully investigated and optimized with initial AgI loading percentage (5%), catalyst dosage (1.0 g/L.), coexisting organics (1.0 mmol/L EDTA) and pH (1-2). The optimal AgI/TiO2 exhibited good stability with little change in activity after 5 cycles. (C) 2015 Elsevier B.V. All rights reserved.