Z-scheme 2D/2D WS2/Bi2WO6 heterostructures with enhanced photocatalytic performance

Herein, we designed and prepared a novel two-dimensional/two-dimensional WS2/Bi2WO6 heterostructure photocatalyst. Firstly, by first-principles calculations, we found that Bi2WO6 and WS2 could form a stable WS2/Bi2WO6 heterostructure with a type-II band alignment structure. Supporting by the theoretical prediction, a series of WS2/Bi2WO6 heterostructures with different amounts of WS2 were synthesized via a facile hydrothermal method. The WS2/Bi2WO6 heterostructures exhibited higher photocatalytic activity in degradation of rhodamine B and oxytetracycline under visible light irradiation than the pure Bi2WO6 and WS2. And the WS2/Bi2WO6 heterostructure had a large specific surface area and good photo-stability. The photoluminescence spectra and photoelectrochemical measurements showed that the WS2/Bi2WO6 heterostructure possessed the ability to facilitate the separation and transfer of photo-generated carries. The active species generated in the photocatalytic system were photo-induced holes, singlet oxygen, and superoxide anion, which were verified by the trapping experiments and electron spin resonance technique. Furthermore, a Z-scheme photocatalytic mechanism was proposed.