A novel defect reassembly strategy for NH2-MIL-125(Ti) to enhance the photocatalytic NO removal activity

Photocatalysis technology has been widely used to eliminate typical air pollutants, but its further application is limited by the finite visible light response and severe charge carrier recombination. In this study, through a simple defect reassembly strategy, the carboxyl group of highly photosensitive eosin Y is successfully coordinated with the exposed Ti clusters in the defective NH2-MIL-125(Ti) to improve photocatalytic activity. The results demonstrate that the NO removal rate of the optimal sample (named D-NM-125/EY) is about 62.05%, which is 1.62 times that of the original NH2-MIL-125(Ti). The UV–Vis, PL, and photochemical characterization analysis confirm that the incorporation of eosin Y significantly can enhance the visible light absorption capacity and promote the photogenerated carriers separation, which may be due to that eosin Y can more easily absorb and utilize visible light to produce more photogenerated electron-hole pairs. Combining ESR with in-situ DRIFTS analysis, the possible photocatalytic mechanism is revealed, in which the reactive oxygen species generated in the photocatalytic process are the key factors for the successful degradation of NO into less toxic substances. This study will provide a new strategy for modifying MOFs photocatalysts to solve typical air pollution problems.