Synthesis of Ta3N5/Bi2MoO6 core-shell fiber-shaped heterojunctions as efficient and easily recyclable photocatalysts

Developing efficient and easily recyclable photocatalysts has drawn much attention. Herein, we report the design and synthesis of Ta3N5/Bi2MoO6 core-shell fiber-shaped heterojunctions as a kind of efficient and easily recyclable photocatalyst. Ta3N5 nanofibers have been prepared by an electrospinning-calcination-nitridation method, and then in situ growth of Bi2MoO6 on their surfaces is realized by a solvothermal method. The resulting Ta3N5/Bi2MoO6 heterojunctions are composed of porous Ta3N5 nanofibers (diameter: similar to 200 nm) whose surfaces are decorated with Bi2MoO6 nanosheets (length: 100-200 nm; thickness: similar to 15 nm). They exhibit remarkably enhanced photocatalytic activities for the degradation of rhodamine B (RhB) and para-chlorophenol (4-CP) under visible light, compared with pure Bi2MoO6 or Ta3N5. In particular, the heterojunction with a Ta3N5/Bi2MoO6 molar ratio of 1/1 achieves the highest photodegradation efficiency of RhB (99.5%), which is about 1.85 times that (53.7%) of Bi2MoO6 and 1.66 times that (60.1%) of the mechanical mixture (49.8 wt% Bi2MoO6 + 50.2 wt% Ta3N5). The superior photocatalytic properties can be attributed to the efficient separation of photo-induced electron-hole pairs and the high BET surface area. The dominant active species are determined to be superoxide and the photogenerated holes. More importantly, the Ta3N5/Bi2MoO6 heterojunction can be easily recycled by simple sedimentation while maintaining good stability. This work offers more valuable insights into the design of efficient and easily recyclable photocatalysts for environmental remediation.