Construction of magnetically separable hierarchical Z-scheme NiFe 2 O 4 @Bi 2 Sn 2 O 7 heterojunction with enhanced visible-light photocatalytic activity

The magnetic photocatalysts play an important role in practical application. Herein, a novel magnetic hierarchical Z-scheme NiFe 2 O 4 @Bi 2 Sn 2 O 7 heterojunction photocatalyst was fabricated by hydrothermal strategy. The structure, micromorphology and physical properties of the as-prepared products were analysed, and the photocatalytic performance was carried out via photocatalytic degradation of tetracycline hydrochloride under visible-light irradiation. The longest average carrier lifetime of the NiFe 2 O 4 @Bi 2 Sn 2 O 7 composite is about 2.9 times longer than that of pure Bi 2 Sn 2 O 7 (2.45 ns), thereby achieving the enhanced photocatalytic activity. After a four-cycle photocatalytic degradation reaction, the NiFe 2 O 4 @Bi 2 Sn 2 O 7 composite still exhibits excellent photocatalytic activity and structural stability due to its magnetic property, and this feature is conducive to its practical application. The results demonstrate that NiFe 2 O 4 nanoparticles are uniformly loaded on flower-like hierarchical Bi 2 Sn 2 O 7 , and thus not only forming nanosized Z-scheme NiFe 2 O 4 @Bi 2 Sn 2 O 7 heterostructure, but also making the composite material magnetic. This work provided new perspectives about construction of heterojunction photocatalysts. Graphic Abstract