Facile microwave-assisted synthesis of In2O3 nanocubes and their application in photocatalytic degradation of tetracycline

Abstract

Novel In₂O₃ nanocube photocatalysts were successfully prepared by a facile microwave-assisted synthesis method. The obtained products are nano-sized with square corners and high crystallinity. The In₂O₃ nanocubes possessed high efficiency of electron–hole separation, resulting in high photocatalytic activities for the degradation of tetracycline under both visible light (λ > 420 nm) and full-range light irradiation (360–760 nm), the ratios of which are 39.3% and 61.0%, respectively. Moreover, the calculated positions of the CB and VB under our experimental conditions at the point of zero for In₂O₃ nanocubes are −0.60 V and +2.17 V, respectively. Note that the redox potentials of [O₂/·O₂⁻] and [·OH/OH⁻] are −0.33 V and +2.38 V, respectively, which means that the irradiated In₂O₃ nanocubes can reduce O₂ into ·O₂⁻ without oxidizing OH⁻ into ·OH. It can be concluded that ·O₂⁻ and h⁺ are the main active species of In₂O₃ in aqueous solution under visible light irradiation and full-range light irradiation.