Bio-MIL-100(Fe)\nHeterostructure Construction and Charge\nRegulation: Iron Redundancy Breakthrough in a Fenton-like System

Excellent stability and antioxidant properties of MIL-100(Fe)\n(MF)\nhave made it widely used in water pollution control. However, fully\ncoordinated active sites and slow Fe<sup>3+</sup> reduction due to\nhigh charge transfer resistance limit the Fenton-like performance\nof MF. The redox and secondary mineralization capabilities of metal-respiring\nbacteria (MRB) might be able to optimize and modify MF to address\nthe above bottlenecks. The results demonstrated that MRB (<i>Geobacter</i>) successfully created Fe<sup>2+</sup> coordinatively\nunsaturated sites (CUS) while preserving structural stability and\nformed a magnetic heterostructure using nonstructurally stable Fe<sup>3+</sup>. Compared with MF, MIL-100(Fe)-<i>Geobacter</i> (MFG) had 1.6 times iron content and achieved 1.2–4.9 times\nremoval efficiency for different organic pollutants. In addition,\nMRB secreted extracellular polymeric substances and mediated the formation\nof Fe<sub>3</sub>O<sub>4</sub> while exhibiting excellent interference\nresistance and reusability. Density functional theory calculations\nconfirmed that the charge transfer within the heterostructure made\nthe Fe<sup>3+</sup> interface electropositive, which overcame the\nlimiting step of the slow Fe<sup>3+</sup> reduction rate. Meanwhile,\nFe<sup>2+</sup> CUS acted to improve the reactivity, which together\nenhanced the catalytic performance of MFG. This study highlights the\npotential of MRB as a material modification tool and provides new\ninsights for future biomaterial development and applications in the\nfields of wastewater treatment.