Synergistic Effects of Magnetic Z-Scheme g-C(3)N(4)/CoFe(2)O(4) Nanofibres with Controllable Morphology on Photocatalytic Activity

The rational design of interfacial contacts plays a decisive role in improving interfacial carrier transfer and separation in heterojunction photocatalysts. In Z-scheme photocatalysts, the recombination of photogenerated electron–hole pairs is prevented so that the redox capacity is maintained. Here, one-dimensional graphitic carbon nitride (g-C(3)N(4))/CoFe(2)O(4) fibres were synthesised as a new type of magnetic Z-scheme visible-light photocatalyst. Compared with pure g-C(3)N(4) and CoFe(2)O(4), the prepared composite photocatalysts showed considerably improved performance for the photooxidative degradation of tetracycline and methylene blue. In particular, the photodegradation efficiency of the g-C(3)N(4)/CoFe(2)O(4) fibres for methylene blue was approximately two and seven times those of g-C(3)N(4) and CoFe(2)O(4), respectively. The formation mechanism of the Z-scheme heterojunctions in the g-C(3)N(4)/CoFe(2)O(4) fibres was investigated using photocurrent spectroscopy and electrochemical impedance spectroscopy. We proposed that one of the reasons for the improved photodegradation performance is that the charge transport path in one-dimensional materials enables efficient photoelectron and hole transfer. Furthermore, the internal electric field of the prepared Z-scheme photocatalyst enhanced visible-light absorption, which provided a barrier for photoelectron–hole pair recombination.