BiFeO3/Bi2Fe4O9 S-scheme heterojunction hollow nanospheres for high-efficiency photocatalytic o-chlorophenol degradation

• Published in: Applied catalysis. B, Environmental Environmental, 2022-12, Vol.319, p.121893, Article 121893
• Main Authors: Wang, Ying, Tang, Yaru, Sun, Jianhui, Wu, Xia, Liang, Hao, Qu, Yang, Jing, Liqiang
• Format: Article
• Language: English
• Subjects: BiFeO3/Bi2Fe4O9 heterojunction; Charge separation; Hollow nanosphere; Photocatalytic o-chlorophenol degradation; S-scheme mechanism
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2022.121893

Fabricating phase-mixed heterojunctions is an effective approach to enhance charge separation for high-efficiency photocatalytic o-chlorophenol degradation. In this study, BiFeO3/Bi2Fe4O9 heterojunction hollow nanospheres were prepared by employing a template-adsorption-calcination method. The S-scheme mechanism of BiFeO3/Bi2Fe4O9 heterojunction was confirmed by means of the Kelvin probe and photoelectrochemical measurement. Compared with bare BiFeO3 and Bi2Fe4O9 nanoparticles, the optimized BFO-700 sample displayed 7.7 and 10.7-fold higher photoactivity under visible-light irradiation, respectively. The promoted photocatalytic activity of BFO-700 could be attributed to the increased light absorption due to the hollow structure, the enhanced charge separation due to the S-scheme mechanism via Fe-O channels, as well as the preferential dechlorination via selective adsorption, according to the results of atmosphere-controlled surface photovoltage and transient photovoltage, electron paramagnetic resonance, theoretical calculation, and in-situ Fourier transform-infrared spectroscopy. With the help of liquid chromatography-mass spectrometry and theoretical calculation, a hole-induced selective dechlorination pathway for photocatalytic degradation of o-chlorophenol was proposed. [Display omitted] •Phase-mixed BiFeO3/Bi2Fe4O9 heterojunction hollow nanosphere was successfully prepared.•It displayed superior photoactivities for degradation and mineralization of o-chlorophenol.•S-scheme mechanism of the BiFeO3/Bi2Fe4O9 heterojunction with enhanced charge separation was confirmed.•An interesting Fe-O channel in the interface of the heterojunction was demonstrated to facilitate charge separation.•A hole induced preferential dechlorination due to the selective adsorption was theoretically and experimentally verified.