Oxygen vacancies boosted charge separation towards enhanced photodegradation ability over 3D/2D Z-scheme BiO1−XBr/Fe2O3 heterostructures

Abstract

Generally, Z-scheme heterojunctions with outstanding photocatalytic capacity require electron mediators to boost electrons transfer. But traditional electron mediators generally cause the reduction of visible-light absorption ability, weak durability of photocatalyst, and various backward reactions between semiconductor photocatalyst and redox mediator. Therefore, exploring an appropriate electron transfer mediator for the Z-scheme heterojunction is very desirable. In this study, we dedicatedly designed and prepared oxygen vacancies (OVs) mediated 3D/2D Z-scheme BiO1−XBr/Fe2O3 (BF) composites via a facile hydrothermal process. Notably, introducing rich OVs could enhance the visible-light response and TC adsorption capability of photocatalysts. What's more, the rich OVs could act as the electron mediators of Z-scheme system by capturing photoinduced electrons. These results of transient photocurrent analysis, EIS, and PL demonstrated that introducing rich OVs and constructing 3D/2D Z-scheme heterostructure on BF composites could promote charge separation. The photocatalytic performance of prepared samples was evaluated by tetracycline (TC) removal. And the result demonstrated that the photocatalyst with stronger adsorption capacity showed stronger photodegradation ability. The BF composite with optimal ratio (BF-30) showed the most outstanding ability of TC removal, which were benefited mainly from the synergistic effect of 3D/2D Z-scheme heterojunction and OVs. The possible photocatalytic reaction mechanism of BF(30) was also revealed by active species capture experiments. The present study brought a new opportunity to rationally design OV-rich 3D/2D Z-scheme heterojunction for the enhanced photocatalytic ability.