Regulatable construction of 3D/2D cubic In2O3/copper doped g-C3N4 heterojunction with boost photocatalytic degradation of BPA

Abstract

In this work, a 3D/2D cubic In2O3/Copper doped graphitic carbon nitride (Cu-CN), heterojunction photocatalysts were synthesized using hydrothermal process and further applied to study its photocatalytic properties for bisphenol-A (BPA) degradation. The cubic three-dimensional In2O3 disperse on the surface of Cu-CN two-dimensional sheet was studied by TEM and XRD. The resulting composites of In2O3/Cu-CN, show the highest photocatalytic activity for 15%-In2O3/Cu-CN at optimized ratio under the visible-light irradiation. As compared to both pure Cu-CN and/or In2O3, the optimized composites of In2O3/Cu-CN show 5–7 fold improvement for the degradation of BPA. Specifically, In2O3/Cu-CN with a In2O3/Cu ratio of 15% displays a kinetic value of 0.01/min, whereas pure Cu-CN and In2O3 have a kinetic value of 0.002/min and 0.0015/min, respectively. The significant enhancement of the photocatalytic behaviour of the heterojunction is attributed to the regulated In2O3/Cu-CN, that not only promotes the separation of photo-induced electrons and electron-hole efficiently, but also the transformation of heterojunction interface via the band position in between the Cu-CN and In2O3. Furthermore, the improvement mechanism of achievable activity is discussed in details. Moreover, 15%-In2O3/Cu-CN also exhibits a good stability and photocatalytic activity as verified through four recycling responses. It is evidenced that the superoxide (•O2−) and holes (h+) play a crucial role as reactive species for the photocatalytic degradation of BPA. This study provides a new opportunity for the preparation of metal oxide/Cu-CN, heterojunction photocatalysts, which has promising application prospects in wastewater treatment and pollution controlling.