Bimetallic Fe/In metal-organic frameworks boosting charge transfer for enhancing pollutant degradation in wastewater

In this work, bimetallic InαFe1-αbased MOFs NH2-MIL-68 photocatalysts were successfully synthesized by partial replacing In with Fe for improving photocatalytic degradation of pollutants in wastewater. The results revealed that the charge separation and transportation efficiency in bimetallic NH2-MIL-68 (InαFe1-α) catalysts were significantly enhanced in comparison with the NH2-MIL-68 (In), indicating that the introduction of Fe provided an effective charge carrier transfer route via the metal-to-metal charge transfer process, which could reduce the recombination of photoexcited electrons–holes, facilitate charge separation and transfer efficiency. The mixed-metal NH2-MIL-68 (InαFe1-α) system showed enhanced photocatalytic activities for Cr(VI) reduction and TC-HCl oxidation under visible light irradiation, which outperformed 3.4 and 1.8 times higher than that of the NH2-MIL-68 (In), respectively. Furthermore, the possible catalytic mechanism was proposed to explain the photo-induced charge transfer path in the bimetallic NH2-MIL-68 (InαFe1-α) system.