A Simple One-Pot Method for the Synthesis of BiFeO3/Bi25FeO40 Heterojunction for High-Performance Photocatalytic Degradation Applications

This study presents a facile one-pot synthesis method to fabricate BiFeO₃-Bi₂₅FeO₄₀-Bi₂O₃ heterojunction photocatalysts with controllable compositions and pure phases. Three different binary heterojunctions (BiFeO₃/Bi₂₅FeO₄₀, BiFeO₃/Bi₂O₃, and Bi₂₅FeO₄₀/Bi₂O₃) and a ternary BiFeO₃/Bi₂₅FeO₄₀/Bi₂O₃ heterojunction were formed, all exhibiting significantly enhanced photocatalytic performance for the degradation of methylene blue (MB) and phenol under visible light irradiation, outperforming the individual compositions. Notably, the BiFeO₃/Bi₂₅FeO₄₀ heterojunction achieved the highest degradation efficiency (93.68% and 83.3% for MB and phenol, respectively) as well as excellent stability. Impressively, the phenol degradation efficiency of BiFeO₃/Bi₂₅FeO₄₀ was even over twice that of BiFeO₃ and Bi₂₅FeO₄₀, and four times higher than that of Bi₂O₃. The enhanced photocatalytic activity of the BiFeO₃/Bi₂₅FeO₄₀ heterojunction is primarily attributed to the advantageous S-scheme band alignments that facilitate efficient charge separation and enhance redox capabilities. While other heterojunctions also exhibited improved MB and phenol degradation efficiency, each unique combination of materials led to distinct electronic structures and diverse reaction mechanisms. The simplicity and scalability of the synthesis method, combined with the remarkable photocatalytic performance of these BiFeO₃-Bi₂₅FeO₄₀-Bi₂O₃ heterojunction materials, position them as highly promising candidates for applications in environmental remediation and solar energy conversion.