Fe salt assisted molten salt synthesis of thin Fe doped Bi4Ti3O12 nanosheets for efficiently photocatalytic activation peroxymonosulfate

Bismuth titanate (Bi 4 Ti 3 O 12 , BTO) has been demonstrated as a promising photocatalyst, but suffers from limited visible-light response, rapid recombination of photogenerated carrier, and few applications for the activation of peroxymonosulfate (PMS). In this work, Fe doped bismuth titanate (Fe/BTO) with very small thickness was successfully synthesized via a molten salt method by using Fe salt source. Compared with the conventional Fe/BTO prepared with Fe 2 O 3 source, the Fe/BTO prepared in this work has homogeneous nanosheet morphology with much smaller thickness around 13.8 nm and higher specific surface area. The doped Fe can significantly decrease the band gap, enhance the light absorption and charge separation. As a result, the Fe/BTO exhibits a significantly enhanced ability to activate PMS for the degradation of organic pollutants. By optimizing the Fe content and calcination temperature, the best Fe/BTO can degrade 99 % rhodamine B (RhB) within 15 min under visible light-PMS (L-PMS) condition with a kinetic constant of 0.4168, which is fairly superior to the BTO or the Fe/BTO under the individual light or PMS condition. Mechanistic studies confirm the involvement of 1 O 2 , e - , ·O 2 - , ·OH and SO 4 · - in the degradation process. This work provides a viable and efficient strategy for designing and preparing visible-light-driven Fe/BTO photocatalyst, advancing their potential for environmental remediation applications.