In this study

the nanostructured AgI/BiOI heterojunction photocatalyst was prepared by solvothermal process. AgI/BiOI heterojunction photocatalyst was characterized using X-ray power diffraction (XRD)

scanning electron microscopy (SEM)

transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectroscopy (DRS). The results indicated that the BiOI product had high purity and composed of nanoplates. The DRS results indicated that BiOI had the significant adsorption in the visible light region

and AgI/BiOI heterojuction photocatalysts possessed the red-shift in the visible light. The photocatalytic activity of AgI/BiOI was evaluated by photocatalytic degradation of acid orange Ⅱ under visible light irradiation (λ > 400 nm). It was observed that the photocatalytic degradation efficiency of acid orange Ⅱ was more than 90% within 2 h

which was higher than that of AgI and BiOI. The enhanced photocatalytic activity mechanism was studied by the electrochemical impedance spectroscopy (EIS). The EIS results showed that the impedance value of AgI/BiOI was much lower than that of pure BiOI

leading to the enhanced photocatalytic activity of AgI / BiOI heterojunction photocatalysts.