S-scheme MOF-on-MOF heterojunctions for enhanced photo-Fenton Cr(VI) reduction and antibacterial effects

• Published in: Chemosphere (Oxford) 2023-12, Vol.344, p.140277-140277, Article 140277
• Main Authors: Wang, Longyang, Zhang, Kejie, Qian, Jianying, Qiu, Mengyi, Li, Ningyi, Du, Hao, Hu, Xiao, Fu, Yangjie, Tan, Meng, Hao, Derek, Wang, Qi
• Format: Article
• Language: English
• Subjects: Antibacterial effects; Cr(VI) remediation; MOF-On-MOF; Photo-Fenton; S-scheme
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.140277

The photocatalytic efficiency is commonly restrained by inferior charge separation rate. Herein, the S-scheme MIL-100(Fe)/NH2-MIL-125(Ti) (MN) photo-Fenton catalyst with the built-in electric field (BEF) was successfully constructed by a simple ball-milling technique. As a result, the MN-3 (the mass ratio of MIL-100(Fe) to NH2-MIL-125(Ti) was 3) composite presented the best visible-light-induced photocatalytic ability, in contrast to pure MIL-100(Fe) and NH2-MIL-125(Ti). The reduction efficiency of Cr(VI) almost reached 100% within 35 min of illumination. Moreover, the MN-3 heterojunction also exhibited the highest antibacterial activity, and about 100% E. coli and more than 90% S. aureus were killed within 60 min of illumination. In photo-Fenton system, In the photo-Fenton system, e−, O2•- and Fe2+ played vital roles for Cr(VI) reduction, and •OH, h+ and O2•- and 1O2 were responsible for sterilization. Additionally, 5 cyclic tests and relevant characterizations confirmed the excellent repeatability and stability of the composite. Also, the S-scheme charge transfer process was put forward. This work offers a novel idea for establishing the MOF-on-MOF photo-Fenton catalyst for high-efficiency environmental mitigation. [Display omitted] •MN composites with built-in electric field were synthesized by ball-milling method.•The MN photo-Fenton system showed a great photocatalytic activity.•The established S-scheme charge transfer process accelerates the charge separation.•The mechanism for Cr(Ⅵ) reduction and sterilization was proposed.