Fabrication of Bi2O3/In2O3 p-n heterojunction with enhanced photocatalytic activity by efficient interfacial charge transfer

Facilitating the separation of photogenerated charges is a crucial process in photocatalytic degradation of pollutants. In this study, Bi2O3/In2O3 composites were prepared using a co-precipitation method and subsequently calcined at 400 degree celsius for 1 h. The Mott-Schottky curves confirmed a p(Bi2O3)-n(In2O3) heterojunction was yielded. Due to the significant difference in Fermi levels between Bi2O3 and In2O3, an internal electric field was established at the interface, with field lines directed from In2O3 to Bi2O3. Under illumination, the excited electrons accumulated in the conduction band (CB) of In2O3, while holes gathered in the valence band (VB) of Bi2O3, promoting charge separation and enhancing quantum efficiency. The composite material exhibited the highest photocatalytic activity when the atomic percentage of Bi to In was 1:1, with the first-order reaction rate constant of BI-1 increasing to 0.0149 min(-1), which is 4.3 and 4.4 multiples higher than that of pure In2O3 and pure Bi2O3. Recycling experiments demonstrated that the photocatalytic composite possesses good reusability and structural stability.