Partial chemical conversion strategy for the synthesis of novel Ag-Bi7O9I3-Bi25VO40 heterostructure with improved photocatalytic activity.

Abstract The rational design of two-dimensional (2D) heterogeneous photocatalysts is considered to be one of the effective methods to achieve high-efficiency migration and separation of photo-excited electrons and holes. Nevertheless, if these separated photo-excited electrons fail to be removed as soon as possible, they tend to recombine with photo-generated holes due to their own instability, losing its excellent photocatalytic activity. Therefore, by means of the combination of 2D semiconductor heterostructures and noble metal modifying technology, we reported the preparation of novel 2D Ag-Bi 7 O 9 I 3 -Bi 25 VO 40 composite photocatalyst through a facile partial chemical conversion strategy coupling with photo-reduction method, employing the pre-prepared Bi 25 VO 40 microcubes as starting materials. The resulted Ag-Bi 7 O 9 I 3 -Bi 25 VO 40 ternary heterostructure exhibited outstanding photo-degradation ability by comparison of pure Bi 7 O 9 I 3 , Bi 25 VO 40 as well as Bi 7 O 9 I 3 -Bi 25 VO 40. In addition, some active species produced during the photocatalytic reaction process were identified by the introduction of corresponding trapping agents. The improved photodegradation efficiency might be attributable to the effective separation of photo-induced electrons and holes derived from the energy level difference between two heterogeneous components, unique 2D layered structure, strong internal electric field and the famous "electronic sink effect" of Ag nanoparticles. [ABSTRACT FROM AUTHOR]