Nanoconfinement-Enabled Resistance to Water Matrix Components for Selective Degradation of Micropollutants

Despite recent substantial advances in water treatment, the ability to selectively degrade trace micropollutants in real waters with complex matrix components remains a grand challenge. Here we report rational crafting of graphene oxide (GO)-wrapped defective TiO₂ composite catalysts that creates nanoscopic confinement over the TiO₂ surface within GO, thereby enabling the selective degradation of micropollutants through effectively excluding natural organic matter (NOM) and anions from the nanoconfined catalytic sites. In contrast to unconfined counterparts, the nanoconfined composite catalysts retain high degradation efficiency when exposed to various concentrations of NOM and anions, even in real water samples. Oxygen vacancies in TiO₂ promote electron separation and oxygen adsorption, leading to a 4.9-fold increase in hydroxyl radical concentration within the nanoconfined space compared to the bulk solution. In situ X-ray photoemission spectroscopy and Raman spectroscopy unveil the nanoconfined catalytic sites on the TiO₂ surface, where micropollutants smaller than the pores of GO are effectively degraded, while NOM with a larger size is excluded by GO. Furthermore, the formation of toxic disinfection byproducts is well controlled due to the exclusion of NOM. This work provides a simple yet viable strategy for designing 2D material-wrapped catalysts to selectively degrade target micropollutants in complex real waters.