Tuning Lewis acidity of MIL-88B-Fe with mix-valence coordinatively unsaturated iron centers on ultrathin Ti3C2 nanosheets for efficient photo-Fenton reaction

Iron containing MOFs have been currently estimated as greater candidates for heterogeneous Fenton catalysts due to their open pores and well dispersed metallic components. However, metals in majority of MOFs are bounded by organic linkers, which reduces Lewis acid sites and make them not available for H 2 O 2 activation. Creating coordinatively unsaturated metal centers (CUCs), acting as Lewis acid sites, is a feasible approach for efficient photo-Fenton activity. Here, we successfully synthesized a photo-Fenton CUCs-MIL-88B-Fe catalyst with mixed-valence (Fe II /Fe III ) on ultrathin Ti 3 C 2 nanosheets. The Lewis acidity was probed by TPD-NH 3 and IR-pyridine analysis and tested for pollutants degradation. The results showed that CUCs-MIL-88B-Fe/Ti 3 C 2 displayed highest photo-Fenton activity under visible light irradiation at pH 3.0 and 10 mM H 2 O 2 . This could be attributed with the CUCs, fast H 2 O 2 activation, high Lewis acidity and carrier separation with Ti 3 C 2 nanosheets due to its high charge mobility. Furthermore, CUCs-MIL-88B-Fe/Ti 3 C 2 exhibited a good stability and reusability.