Construction of Z-Scheme BiFeO3/Bi2O4 heterojunction for significantly boosted photocatalytic degradation of tetracycline under visible irradiation

Currently, the development of photocatalysts with high activity and degradation of the emerging pollutants are two research hotspots in environmental field. Herein, a Z-scheme BiFeO3/Bi2O4 heterostructure was constructed by anchoring BiFeO3 nanoparticles on the Bi2O4 with a rod-like structure. The fabricated BiFeO3/Bi2O4 was characterized in detail by UV–vis spectra, XRD, XPS, SEM, and TEM. The photocatalytic decomposition of tetracycline (TC) was performed to assess the photocatalytic performance of BiFeO3/Bi2O4 under visible irradiation. The charge transfer pathway between BiFeO3 and Bi2O4 was clarified based on the band structure and the principal reactive species. BiFeO3/Bi2O4 presents exceptional activity for the photocatalytic degradation of TC. The degradation rate of TC reaches 92 %. The degradation rate constant (0.0847 min−1) of TC by BiFeO3/Bi2O4 was 8.7 and 20.7 times higher than that by Bi2O4 and BiFeO3, respectively. Besides, no obvious loss of activity was observed after 5 cycles of reuse, demonstrating the good stability of BiFeO3/Bi2O4. The significantly boosted activity of BiFeO3/Bi2O4 is because of the superior light-responsive ability and the highly efficient charge transfer resulting from the formation of a Z-scheme heterostructure between BiFeO3 and Bi2O4. The current work offers a new insight into constructing highly efficient composite photocatalysts.