Construction of Z-Scheme g-C(3)N(4)/CNT/Bi(2)Fe(4)O(9) Composites with Improved Simulated-Sunlight Photocatalytic Activity for the Dye Degradation

In this work, ternary all-solid-state Z-scheme g-C(3)N(4)/carbon nanotubes/Bi(2)Fe(4)O(9) (g-C(3)N(4)/CNT/BFO) composites with enhanced photocatalytic activity were prepared by a hydrothermal method. The morphology observation shows that ternary heterojunctions are formed in the g-C(3)N(4)/CNT/BFO composites. The photocatalytic activity of the samples for the degradation of acid orange 7 was investigated under simulated sunlight irradiation. It was found that the ternary composites exhibit remarkable enhanced photocatalytic activity when compared with bare BFO and g-C(3)N(4)/BFO composites. The effect of the CNT content on the photocatalytic performance of the ternary composites was investigated. The photocatalytic mechanism of g-C(3)N(4)/CNT/BFO was proposed according to the photoelectrochemical measurement, photoluminescence, active species trapping experiment and energy-band potential analysis. The results reveal that the introduction of CNT as an excellent solid electron mediator into the ternary composites can effectively accelerate the electron migration between BFO and g-C(3)N(4). This charge transfer process results in highly-efficient separation of photogenerated charges, thus leading to greatly enhanced photocatalytic activity of g-C(3)N(4)/CNT/BFO composites. Furthermore, the g-C(3)N(4)/CNT/BFO composites also exhibit highly-efficient photo-Fenton-like catalysis property.