Fabrication of wide-spectra-responsive NA/NH2-MIL-125(Ti) with boosted activity for Cr(VI) reduction and antibacterial effects

A NA/NH2-MIL-125(Ti) homojunction was prepared by grafting 1-naphthylamine (–NA, a chromophore group) on the –NH2 group in part of NH2-MIL-125(Ti). In-depth investigation of the optical and structural variations was carried out. The results indicated that the lattice structure of NH2-MIL-125(Ti) was well preserved after –NA modification. Whereas NA/NH2-MIL-125(Ti) with 10% –NA ratio exhibited optimal photocurrent response and the lowest charge separation efficiency. In photocatalytic activity experiments, NA/NH2-MIL-125(Ti) showed excellent activity with more than 99% Cr(VI) reduction and 99.999% bactericidal efficiency within 60-min irradiation. Furthermore, the photocatalysts showed good stability after 5 cyclic runs. Then, a mechanism about how the bacteria were killed was proposed, which was mainly contributed by the destruction of the cell membrane by photogenerated singlet oxygen (1O2). The results of this work will open a new route to the synthesis of MOFs for multiple photocatalytic applications.