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 and stringent acidic conditions, which could simplify the operation and significantly enhance organic pollutant degradation efficiency. In this work, an eco-friendly precipitation process was developed to synthesize bimetallic MIL-100(Fe)-based MOFs with both Ti and V as the secondary metal ion at room temperature. The MIL-100(Fe/V) MOF demonstrated a superior antibiotics removal performance than both MIL-100(Fe) and MIL-100(Fe/V) MOFs. The mechanism study demonstrated that active V⁴⁺/V⁵⁺ redox sites could enhance the 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 the Ti-doping without mixed valence states. Thus, using a second metal species with mixed valence states could be a promising approach to form bimetallic MOFs with significantly enhanced photocatalysis-self-Fenton performances for environmental remediation.