ZnO/ZnFe2O4/Ag hollow nanofibers with multicomponent heterojunctions for highly efficient photocatalytic water pollutants removal

Novel ZnO/ZnFe2O4/Ag hollow one-dimensional multicomponent heterojunctions with different ZnO/ZnFe2O4 ratios were successfully obtained via a simple electrospinning method. These multicomponent heterojunctions exhibited a largely enhanced photocatalytic performance for various reactions compared with pure ZnFe2O4 without heterojunctions, ZnO/ZnFe2O4 and ZnFe2O4/Ag with single heterojunctions. The enhancement can be mainly ascribed to the synergism of multicomponent heterojunctions, which can significantly improve the optical absorption abilities, prompt the separation of photogenerated carriers, and depress the recombination of electron-hole pairs. Hence, the simultaneous and efficient generation of electrons and holes with strong reduction and oxidation abilities, respectively, can lead to effective reaction with the target degradants. In addition, the unique hollow nanofiber structure can also prompt the activities by decreasing the distance for charge carrier transfer to the solution during the photocatalytic process. Additionally, the influence of the number of heterojunctions on the photoactivity was also discussed via varying the ZnO loading amount. This work displays an ingenious design to elevate photocatalytic performances of spinel ZnFe2O4 for solving its biggest problems in the photocatalytic applications, and reveals the rational design of photocatalysts for efficient water pollutants removal.