NH-MIL-88B (Fe In ) mixed-MOFs designed for enhancing photocatalytic Cr(vi) reduction and tetracycline elimination.

Aiming at solving the issue of wastewater purification, this work synthesized NH-MIL-88B (Fe In ) photocatalysts by a simple one-pot method, which was employed for photocatalytic reduction of Cr(vi) and oxidation of TC-HCl. Compared with traditional NH-MIL-88B (Fe) photocatalysts, NH-MIL-88B (FeIn) displayed excellent photocatalytic performance; the photocatalytic redox rate for Cr(vi) and TC-HCl reached 86.83% and 72.05%, respectively. The good photocatalytic performance might be attributed to the metal-to-metal charge transition (MMCT) between Fe-O clusters and In-O clusters formed by doping In(iii) into NH-MIL-88B (Fe), which provides effective active sites for the photocatalytic reduction and oxidation routes. Besides, the synergistic effect of the ligand-to-metal charge transition (LMCT) and MMCT expands the separation and transfer of photogenerated carriers and inhibits the recombination of electron-hole pairs, thus effectively improving the photocatalytic performance. Therefore, this work could provide a new method for the construction of mixed metal MOFs for the photocatalytic degradation of pollutants.