Ultrasonic-assisted fabrication of Cs2AgBiBr6/Bi2WO6 S-scheme heterojunction for photocatalytic CO2 reduction under visible light

In this manuscript, Cs2AgBiBr6/Bi2WO6 nanocomposites was fabricated via an ultrasonic-assisted process. The activity of the as-obtained Cs2AgBiBr6/Bi2WO6 nanocomposites for photocatalytic CO2 reduction was studied under visible light. The as-obtained Cs2AgBiBr6/Bi2WO6 nanocomposites show a superior activity for photocatalytic CO2 reduction to produce CH4 and CO, with an optimum activity achieved over 0.5 Cs2AgBiBr6/Bi2WO6. The obvious superior activity observed over Cs2AgBiBr6/Bi2WO6 nanocomposites as compared with bare Cs2AgBiBr6 and bare Bi2WO6 as well as a mechanical mixture of Cs2AgBiBr6 and Bi2WO6 can be owe to the fabrication of an efficient S-scheme heterojunction, which accelerates the separation of the photogenerated charge carriers in Cs2AgBiBr6 and Bi2WO6 without sacrificing the high redox capability of Cs2AgBiBr6 and Bi2WO6. This work demonstrates that the coupling of two photocatalytic materials with staggered band alignment to form an S-scheme heterojunction is an effective strategy to develop efficient photocatalytic systems and also highlights the promising role of using lead free perovskites in photocatalysis.