BiOI/α-AgAl0.4Ga0.6O2 heterostructures with controllable visible-light absorption and enhanced carrier separation efficiency

•Synthesis of BiOI/α-AgAl0.4Ga0.6O2 with heterojunctions by precipitation method.•Controllable UV-vis absorption attributed to overlapped band gap of two phases.•Enhanced separation efficiency of photoinduced carrier due to heterojunctions.

BiOI/α-AgAl0.4Ga0.6O2 heterostructures are synthesized by a precipitation route. The results show that flower-like BiOI microspheres grow on platelet-like α-AgAl0.4Ga0.6O2. With regard to the heterojunctions, the visible-light absorption edges expand from 470 to 650 nm by controlling the ratio of α-AgAl0.4Ga0.6O2 to BiOI. Photoluminescence spectra demonstrate that the BiOI/α-AgAl0.4Ga0.6O2 exhibits lower emission intensity than the BiOI and α-AgAl0.4Ga0.6O2, indicating the enhancement of carrier separation efficiency which is also verified by electrochemical impedance spectroscopy. Thus, the BiOI/α-AgAl0.4Ga0.6O2 heterostructures can efficiently utilize visible light and facilitate carrier separation.