Sheet-on-sheet TiO2/Bi2MoO6 heterostructure for enhanced photocatalytic amoxicillin degradation.

Developing sheet-on-sheet (2D/2D) heterostructure with built-in electric field (BIEF) is effective in boosting the performance of photocatalysts for emerging contaminants degradation. Herein, the 2D/2D microtopography and (-)TiO2/(+)Bi2MoO6 BIEF were precisely integrated into hierarchical nanosheets, which can provide the basis and driving force for charge transfer both in in-plane and interface of heterojunction. The prepared photocatalyst (TiO2/Bi2MoO6) showed high-efficiency and stable performance for photocatalytic amoxicillin (AMX) degradation, which was 18.2 and 5.7 times higher than TiO2 and Bi2MoO6, respectively. More importantly, TiO2/Bi2MoO6 showed more efficient photocatalytic activity and photogenerated charge separation than TiO2@Bi2MoO6 (different morphology). Besides, four possible pathways of AMX degradation were proposed depending on Gaussian calculations and intermediates analysis by GC-MS and HPLC-TOFMS. This work sheds light on the design and construction of unique 2D/2D heterostructure photocatalysts for AMX degradation.