▎ 摘　　要

The modification of photocatalyst was the vital task for improving photocatalytic performance. Inspired by multi-level effect and activation regions of N atom, multi-level bismuth-based spheres (Bi2Ti2O7) and N-doped graphene quantum dots (N-GQD) were constructed for the photocatalytic application. Experiments demonstrated that the N-GQD/Bi2Ti2O7 multi-level spheres showed higher photocatalytic performance due to the multi-level effect and activation regions. Meanwhile, a series of characterizations proved that the separation efficiency of electron-hole pairs was improved after the N-GQD modifications. A possible mechanism was proposed for investigating N-GQD/Bi2Ti2O7 materials in the photocatalytic field.