Hierarchical heterostructures of Bi₂MoO₆ on carbon nanofibers: controllable solvothermal fabrication and enhanced visible photocatalytic properties

In this paper, a facile two-step synthesis route combining an electrospinning technique and solvothermal method has been presented as a straightforward protocol for the exploitation of Bi₂MoO₆–carbon nanofiber (CNF) hierarchical heterostructures, which are composed of Bi₂MoO₆ nanosheets on the surface of CNFs. Photocatalytic tests show that the Bi₂MoO₆–CNF heterostructures possess a much higher degradation rate of Rhodamine B (RB) than pure Bi₂MoO₆ under visible light. The enhanced photocatalytic activity may be attributed to the extended absorption in the visible light region due to the Bi₂MoO₆ nanosheets, and the effective separation of the photogenerated carriers driven by the photoinduced potential difference produced at the Bi₂MoO₆–CNF heterojunction interface. Moreover, the heterostructures could be recovered easily by sedimentation without a decrease in their photocatalytic activity. The morphology of the secondary Bi₂MoO₆ nanostructures could be controlled by adjusting the experimental parameters, including the precursor concentration, temperature and solvent during the solvothermal process. As a result, different morphologies of Bi₂MoO₆–CNF heterostructures, with Bi₂MoO₆ nanosheets, nanoparticles, nanoflowers and nanorods, were successfully achieved.