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

A novel polyaniline (PANI)/SnO heterojunction composed of PANI nanofibers and SnO nanosheets was fabricated by a facile physical milling technique. Modification of SnO 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/SnO 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 SnO alone. This improvement is due to the p-n heterostructure formation in PANI/SnO. Moreover, the outcome of reactive species capturing experiments demonstrated that in PANI/SnO, 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.