Oxygen Vacancy-Enriched Bi2o3/Bifeo3 P-N Heterojunction Nanofibers With Highly Efficient Photocatalytic Activity Under Visible Light Irradiation

The construction of heterojunctions is considered an effective way to improve the photocatalytic performance of bismuth-based photocatalysts. In this research, Bi2O3/BiFeO3 heterojunction nanofibers with rich oxygen vacancies were successfully synthesized via the in-situ growth of Bi2O3 nanosheets on the surface of BiFeO3 nanofibers, and were then reduced in N, N-dimethylformamide (DMF) via the solvothermal method for different times. The composite ratios and oxygen vacancy concentrations were then systematically optimized. The optimal composite with the molar ratio of BiFeO3:Bi2O3 = 1:1 and solvothermally reducted in DMF for 3 h was found to completely degrade the tetracycline hydrochloride (TC) solution within 120 min, and its photodegradation rate was 8.7 and 5.4 times higher than those of pure BiFeO3 and Bi2O3, respectively. The enhancement can be ascribed to the synergistic effect of the p-n heterojunction formed at the interface and oxygen vacancies produced on the surface, which significantly increased the absorption of visible light, inhibited the recombination of photogenerated electron-hole pairs, and accelerated the separation and transfer of photogenerated charges. Moreover, the obtained oxygen vacancy-enriched Bi2O3/BiFeO3 heterojunction nanofibers exhibited good cyclic stability and magnetic separation capability, and therefore have potential applications in practical sewage treatment.