Construction of ZnO/PPy/PAN Nanofiber Membrane as Heterojunction Photocatalyst with Enhanced Photocatalytic Activity

The construction of semiconductor heterojunctions is an effective way to enhance the photocatalytic activity. In this work, n–p heterojunction composed of ZnO nanorods and polypyrrole (PPy) nanospheres were loaded on polyacrylonitrile (PAN) nanofibers to fabricate ZnO/PPy/PAN nanofiber membranes (ZnO/PPy/PAN NFMs) via electrospinning, hydrothermal synthesis and chemical polymerization. The results showed that the photodegradation rate of ZnO/PPy/PAN NFM was about 4.8 times higher than that of ZnO/PAN NFM. Moreover, the membrane exhibited good cycling stability, which maintained the removal efficiency of rhodamine (RhB) at 79% after five cycles. The enhanced photocatalytic activity was mainly ascribed to the synergistic effect of PAN nanofibers adsorption and n–p heterojunctions catalysis, resulting in a narrow bandgap, an increase in the absorption of visible light and the separation efficiency of electron–hole. Meanwhile, the degradation mechanism of ZnO/PPy/PAN NFMs was proposed. This work provides a promising strategy to construct n–p heterojunction photocatalysts for removing organic pollutants in wastewater.