Novel 3D multi-layered carbon nitride/indium sulfide heterostructure for boosted superoxide anion radical generation and enhanced photocatalysis under visible light

Superoxide anion radical (O2−) plays an important role in the selective photocatalytic degradation of recalcitrant organic pollutants in a complex aquatic environment. However, the yield of O2− is low due to the low charge utilization and limited visible light absorption. Here, we built a novel there-dimension (3D) multi-layered CNIS (carbon nitride/indium sulfide) heterostructure via a facile molecular self-assembly route, in which morphological engineering and heterostructure construction were synergistically used. Results showed that the formation of the type-II heterojunction between CN and In2S3 via In-N bonds significantly shifted the band positions and increased the density of band tail, facilitating high absorption of visible light and suppressing the charge carrier recombination. Additionally, the ordered sheet-to-sheet architecture of 3D multi-layered CNIS heterostructure with strong anisotropy accelerated exciton dissociation and provided abundant diffusion channels. Therefore, the novel 3D multi-layered CNIS heterostructure exhibited effective photocatalytic activity towards O2− generation (11.54 μmol/L min−1), causing 83 % removal of tetracycline (TC) in 10 min under visible light.