GQD/Bi2O3 Composite for high-efficient photocatalysts

Abstract

Bismuth oxide (Bi2O3) is one of the potential visible-light photocatalytic materials, however, due to low electron mobility and short minority carrier diffusion length, the photocatalytic activity of Bi₂O₃ is restricted. The GQD/Bi₂O₃ composites were synthesized stably depositing single-crystalline graphene quantum dots (GQDs) with absorption edge at ~10nm, prepared by using a top-down method. The GQDBi₂O₃ heterojunctions were successfully established, the photo-generated electrons transfer from the Bi₂O₃ to the GQDs at the interface of the GQD-Bi₂O₃ heterojunctions, result in efficient electron-hole pairs separation and higher photocatalytic efficiency. The optimum visible performance is achieved at GQD content of 1.0 wt %, the RhB dye was nearly completely decoloured after 90 min of visible-light irradiation, and then decrease at higher doping levels due to the thicker GQD layer will cover the active sites of Bi₂O₃, thus leading to the greatly reduced catalytic activity.