Visible-light photocatalytic capability and the mechanism investigation of a novel PANI/Sn3O4 p-n heterostructure

A novel polyaniline (PANI)/Sn3O4 heterojunction composed of PANI nanofibers and Sn3O4 nanosheets was fabricated by a facile physical milling technique. Modification of Sn3O4 with a PANI conductive polymer contributes to facilitating interfacial charge transfer efficiency, and thus, significantly enhances the visible-light Rhodamine B (RhB) photo-degradation. Results indicate that PANI/Sn3O4 heterostructures with 10 wt% PANI reached the maximum degradation efficiency (around 97%) for RhB within 5 h, which is 2.27 times higher than that of Sn3O4 alone. This improvement is due to the p-n heterostructure formation in PANI/Sn3O4. Moreover, the outcome of reactive species capturing experiments demonstrated that in PANI/Sn3O4, holes made the largest contribution to RhB degradation under visible light illumination, while hydroxyl radicals showed less significance under the same conditions. In addition, the photocatalytic mechanism was proposed based on evidence from the reactive species test and energy band structure analysis.