Discrete heterojunction nanofibers of BiFeO/BiWO: Novel architecture for effective charge separation and enhanced photocatalytic performance.

Designing and constructing one-dimensional (1D) discrete heterojunctions comprise an ideal strategy to improve the charge-separation efficiency and enhance the photocatalytic activities of semiconductor materials. Here, a novel architecture of discrete heterojunction nanofibers (DH-NFs) was obtained by growing BiWO nanosheets (NSs) on electrospun BiFeO nanofibers (NFs) via solvothermal technology. The charge-separation efficiency of BiFeO/BiWO DH-NFs was approximately 2 times higher than that of BiFeO NFs and BiWO NSs. As expected, the BiFeO/BiWO DH-NFs exhibited enhanced photocatalytic activities for oxygen evolution and RhB degradation. The reaction rates of BiFeO/BiWO DH-NFs for oxygen evolution and RhB degradation were 18.3 and 36.7 times higher, respectively, than those of BiFeO NFs, and 31.9 and 8.7 times higher than those of BiWO NSs, respectively. The improved charge-separation efficiency and enhanced photocatalytic activities of BiFeO/BiWO DH-NFs could be attributed to the following three points. The 1D heterojunctions could realize the separation and axial transport of photogenerated charges. The discrete structure could facilitate the spatial separation of redox reaction sites as well as photogenerated charges. The high surface area of BiFeO/BiWO DH-NFs might provide more active sites for photocatalytic reaction. Moreover, the BiFeO/BiWO DH-NFs possessed good recycling performance owing to the magnetic-separable property derived from the ferromagnetic behavior of BiFeO.