LAUSR

Abstract Typically, Z-scheme heterojunctions with excellent photodegradation capability need electron mediator to assist electron transfer, such as redox water mediator and noble metal nanoparticles, but redox water mediators usually cause weak photoabsorption capability and constancy of the photocatalyst, and the noble metal nanoparticles as electron transfer mediator are costly and suffer from various reverse reactions between the redox mediators and the photocatalysts. In this work, oxygen vacancies (OVs)-assisting 2D/2D Z-scheme BiO1-XBr/g-C3N4 (OV-BOB-CN) photocatalysts were synthesized successfully via a simple hydrothermal treatment. Notably, the introduction of OVs is not only to improve visible-light absorption capacity of photocatalyst reflected by UV–vis DRS, but more importantly, it can act as electron mediator in capturing and shuttling electrons of Z-scheme heterostructure to accelerate the separation rate of photogenerated carriers, which was demonstrated by transient photocurrent analysis, EIS, and PL results. The suitable ratio of OV-BOB-CN (OV-50BOB-50CN) showed optimal photodegradation activity for RhB, which was mainly owed to the synergistic reaction between 2D/2D Z-scheme heterostructure and OVs. The photocatalytic mechanism of OV-BOB-CN was revealed by free radical trapping experiments. In conclusion, this work provided a new protocol to design 2D/2D Z-scheme photocatalyst involved OVs, thus guiding a new way to further enhance degradation activity of photocatalyst.