Enhanced visible-light-driven photocatalytic degradation via in-situ AIS/ZIS high-low junctions.

The I-III-VI QDs Ag-In-S (AIS) exhibits excellent properties in photocatalysis because of the adjustable band gap, wide light absorption range, and multiple active sites. Introducing homologous or heterogeneous ions not only derives the composition into quaternary/ quinary quantum dots but also generates new sulfide QDs to form composites, which is an effective strategy to promote photoactivity. In this work, we in-situ synthesized the AIS/ZIS (AgInS/ZnInS) composite photocatalyst by introducing Zn and changing the reaction temperature. We found that the composite photocatalyst could efficiently photodegrade larger concentrations of RhB than that of the previous reports. The superior photocatalytic activity was due to the formation of the type I high-low junction, which could effectively separate carriers. The photoelectrons on the CB of AIS reacted with dissolved oxygen to produce strongly oxidative O, which degraded RhB into intermediates and eventually into CO and HO. This work not only reports an excellent photocatalyst but also offers new ideas on the design and manufacture of highly efficient high-low junction photocatalysts.