Room-temperature synthesis of V-doped MIL-100(Fe) bimetallic MOF with superior antibiotics removal performance through the synergistic effect from photocatalysis and Fenton reaction

The photocatalysis–self-Fenton technique combines photocatalysis with the Fenton reaction to utilize photogenerated electrons to sustain the Fe³⁺/Fe²⁺ cycle without external H₂O₂ source or stringent acidic conditions, which could simplify the operation and significantly enhance the organic pollutant degradation efficiency. In this work, an eco-friendly precipitation process was developed to synthesize bimetallic MIL-100(Fe)-based metal-organic frameworks (MOFs) with both Ti and V as secondary metal ions at room temperature. Compared with both MIL-100(Fe) and MIL-100(Fe/Ti) MOFs, the MIL-100(Fe/V) MOF demonstrated superior antibiotic removal performance. A mechanistic study demonstrated that active V⁴⁺/V⁵⁺ redox sites could enhance charge carrier separation, participate in the self-Fenton reaction to generate more ·OH, and facilitate the reduction of Fe³⁺ through a spontaneous redox cycle than Ti doping without mixed valence states. Thus, the use of a second metal species with mixed valence states could be a promising approach to form bimetallic MOFs with significantly enhanced photocatalysis–self-Fenton performance for environmental remediation.