AgI-BiOI Spherical Solid Solutions with Enhanced Visible-Light Photocatalytic Performances

Recently, AgI and BiOI semiconductors (or their composites) have been widely investigated and demonstrated to be novel and efficient visible-light photocatalytic materials, while seldom investigations about the AgI-BiOI solid solutions with adjustable band gap and band edge have been reported. In this study, Agx(BiO)1-xI spherical solid-solution photocatalysts with controllable band structure were prepared by the combination of in situ ion-exchange route and a following low-temperature calcination process by using BiOI microspheres as the precursor. The influence of AgI amount on the microstructures and photocatalytic performance of AgI-BiOI solid solutions was discussed. It was found that the structure stability of BiOI could be greatly enhanced after the formation of AgI-BiOI solid solution, and the resultant samples show a controllable band gap in the range of 1.76-2.19 eV. Experimental results showed that the prepared Agx(BiO)1-xI solid solution exhibited a much better visible-light photocatalytic activity and stability than the pure BiOI. When the AgI amount was 1 at.%, the resultant Agx(BiO)1-xI (x = 0.01) solid solution showed the best photocatalytic activity, and its rate constant (k = 0.039 min-1) was about 3 times that of the pure BiOI even after 4 cycles of photocatalytic reaction. Considering its facile preparation from aqueous solutions, the present synthesized method of Agx(BiO)1-xI solid-solution photocatalyst can provide new insight for the development of other visible-light photocatalytic materials.